Yes.  There are plenty of favorable trip reports on both in the archives.

Yup!  What hype?

1 to 5 mil wetsuit, depending on your body and cold-resistance.  
Except for occasional thermoclines, the water temp should be in the
high 70s to 80 during that time.  Crossing is ALWAYS rough.  

What you should worry about the most is your own ability to be self-
reliant in strong and unpredictable currents.  In 1992 I recommended
a diver to have at least a couple hundreds of dives under the belt
before attempting this location.   I still hold that view, after a
return trip there 4 years ago.

-- Bob.

Sid I dive Cocos 4 years ago with the aggressor, the crossing was long 40
hours, and the boat was in need of a refit. However the diving was out of this
world. We were mored next to the Sea hunter which looked a newer boat. it is
also a little quicker than the Agressor. When I go again I will use the sea
hunter. Ther e is no Hype it is well worth the trip. If you can try to extend
your stay in Costa Ricca I did not and it is something I regret now.

We dove Cocos a little over two years ago and did the Okeanos.  While the
crew was very accomodating, it was in bad need of refurbishing, so I would
look to the Sea Hunter if this has not been done.

The diving is some of the best that I have ever done, but also some of the
most demanding.  It is definitely not for newbies.  One of the guys in our
group only had a hundred dives and was beat up quite a bit by the
currents -- to his credit he never gave up and never whined -- must have
been his Texan blood.

We dove the whole time in Polartecs and never got chilled, although some in
our group had on 3mms, vests, and hoods.........  The crossing is rough and
takes around 36 hours, but IMHO it is worth every minute.  Take some
Scopolamine patches if you get seasick very easy.  Enjoy your trip!