I just recently dove in Puerto Vallarta...  in early June actually.
Anyways...  I enjoyed the Marietta's islands the most, but it was all great
diving.  I saw sea turtles, plenty of fish, a few giant manta rays....  Like
I said, great diving.  Though in defense of Chico's, I did dive with them
once and they seemed to be great.  They were by far the cheapest and the at
least the divemaster that was with my group was very safety conscious.
Again, I only dove with them once so I cannot give 100% assurances, but the
time I went it was great and they were knew alot about the area.  How ever
you decide to go...  have fun!!  There's great diving down there!