I liked an air integrated Cochran model I was trying out once, for a
company who planned to build a similar model. How sweet it was - told
me everything I could ever want to know about my dive.  Dang, I liked
the thing.  Several of us were using them during a week of trimix dives
in the Eastern basin of Lake Erie.  They were lovely at depth, but at
the last 2 stops, above maybe 40 ft, they'd all start beeping like mad
and stop timing - not a good thing at all.  About the 3rd dy out, we
figured out that the depth finder on the boat interfered with the
signals from the transmitters.  What a good time THAT would have been
if we hadn't been wearing bottom timers and had backup tables cut.
Worthless, they were...... but hey you usually have to find these
things out the hard way.  Obviously, I did.

Perhaps the shop has rental models of the BC's you want and you could
try those in the pool?

Welcome to the confusion of selecting diving equipment.  Now you know why so
many of us have so much equipment sitting around we never use any more.

You have confused a few terms.  Air integrated refers to your computer.  Air
integrated computers take some form of gas pressure input and include some
pressure related information through the computer.  The information either
comes from a hose attached to the computer or a remote unit mounted on the
first stage, that communicates wirelessly with it.  All air integrated
computers tell the user the pressure in the tank.  Most also provide other
information, things like how long you can remain at your current depth at
your current breathing rate or when, based on your remaining gas supply, you
should begin your ascent.

The other issue is whether to use a traditional octopus, a necklaced
alternate or a combination BCD inflator/alternate.  You know what a
traditional octopus looks like and, by now, you seem to have a pretty good
idea what a combination inflator/alternate looks like.  The necklaced
alternate is another form of alternate second stage, usually on a slightly
shorter than normal hose, that has a bungie or surgical tubing necklace
attached.  The necklace goes around your neck and the alternate goes just
under your chin.  With this configuration, as with the combination
inflator/alternate, in an air sharing event, the primary second stage is
donated to the out of air diver and the alternate is used by the diver
wearing it.  Having it close under the chin increases the odds that the OOA
diver will reach for the regulator you want them to have anyway and is as
good or better than any other configuration at ensuring that you can fine
your alternate quickly even in a crisis situation.

Integrated Computers

The issues I have with air integrated computers include display, information
and reliability issues.
Display - The air integrated computers I'm familiar with display the
information the programmer things is most critical in any given situation.
While most, perhaps all, have alternate screens that give the "normal
information" you want from a computer, the "critical information" is either
on screen until  you act to get other information or one of two or more
displays that alternate.  The fact is, what the programmers think is most
critical does not always agree with what I think is most critical.  On a
planned no deco dive, I want such things as dive time, no deco time, and psi
all the time.  I don't mind if the computer shows me something it thinks is
important in addition to the basic information.  I just don't like the fact
that some show it to me instead of the information I'm most interested in.
Informtion - My wife's air integrated computer confused the hell out of her
at first.  She knew that our dives normally last about an hour, no matter
how deep we start out.  Just a few minutes into the dive, her computer was
telling her she had to begin her ascent in only a few minutes.  Of course,
the computer was really telling her how long she could safely remain at her
current depth, not how long her dive would last if she moved to a shallower
depth.  The information was not wrong, it just wasn't what she needed when
doing the kind of mulitlevel dive that computers facilitate.
Reliability - Reliability issues are different depending on the type of
computer you have.  If the computer is attached to a hose, you have a
directly opening into your computer.  That hose and it's connections are one
of the more common failure points in scuba equipment.  Computers that use a
remote sensor and wireless communication depend on a higher level of
technology which, almost by definition, can go wrong in more ways.  Star
mentioned one of them lost communication.  I had not heard of a unit that
got interference from a boat depth finder.  As she noted, that's a pretty
serious problem.  I have heard of units that got interferance from camera
strobes as well as some that lost communication because the tanks was
between the sending and receiving units.  If If  you have a problem with
your pressure measuring and reporting system, it's easy, with no particular
safety concerns, to beg borrow or rent an analog gauge.  If what went wrong,
however, is part of your computer, every computer manufacturer in the world
recommends you sit out at least 24 hours before diving with a different
computer.

Combination Inflator/Alternate

The choice between a combination inflator/alternate and one of the other
options, is a bit harder.  Originally, I had a standard alternate.  Later, I
purchased a combination inflator/alternate.  Mine was, since I still have
it, is, an Oceanic Air Source.  The key things that led me to my unit are
how well it breathes, the availabilty of service, and the ability
comfortably turn my head in either direction while using it.  The last item
was the decisive one.  The Oceanic, at that time, came with a slightly
longer hose, making it more comfortable to use.  At the time, standard
training taught OOA divers to go for the octopus.  Accordingly, I developed
a  habit of informing my fellow divers, that if they needed assistance from
me, they should take the regulator from my mouth rather than try to use my
alternate.  I mentioned the service issue.  I got around it by finding a
local dealer that serviced Oceanics and US Divers, which is what my primary
was back then.  I did not regret, or change, my choice until other
configuration changes forced me to reconsider it.  I liked my
inflator/alternate and, if I were to dive with the same BCD, would use it
again.  The advantages, to me, outweigh the disadvantages.  If you buy
either of your regulators from an unofficial retailer, like buying Scuba Pro
from Liesure Pro, you may introduce a service issue that makes it more
desirable to have a primary and secondary by the same manufacturer.

I currently use a necklaced alternate because the combination unit does not
work well with a plate and harness system.  My SeaQuest BCD provided a means
to secure my combination inflator alternate so that it stayed where I wanted
it, but remained available if I wanted to breathe from it.  The harness on
my plate did not.  I could find no way to secure the somewhat longer hose
that did not also cause problems getting it in a hurry if I needed it.  I
liked the system well enough to try.  Eventually, I gave up and installed a
necklace alternate.  In my personal opinion, the necklaced alternate is the
best single equipment idea to be developed by the cave diving community.  It
works with my current plate and harness as well as my inflator/alternate
worked with my jacket style BCD.  If you are considering a plate, harness
and wing configuration, which I strongly recommend you at least try before
buying, or any other back inflation system, be sure that an
inflator/alternate works well with it before you buy.  If it does, it's not
a bad choice.  If it doesn't, be sure to give a necklaced alternate a try.

I don't know if you mentioned where you dive or not, but no matter where it
is, it's likelty that there are people around that use some form of DIR like
configuration.  Those of us that do, generally got there the hard way and,
for the most part, would love to save others the financial pain of multiple
equipment replacements.  If you see some people using metal plates, wings,
primary hoses 5 feet or longer, and necklaced alternates, find some time to
talk with them about their configuration.  You may find someone, like me,
that has access to more than one set and would be happy to help you set one
up and try it.  You never know until you ask.

The only other suggestion I have is something that's already been said.
Rent a variety of equipment until you have a better idea what you want, then
buy it.  You'll still make some mistakes, but they'll cost you less.

Lee

I said "almost."

;-P

*