ASMS is better.
  Assuming you are doing MS!  
 
PittCon has always been, first and foremost, a trade show to which people come to see the latest hardware "in person". The majority of the vendors send (at least some) technical people to the meeting, and you can walk around the exbibit floor and get specific questions answered (reasonably) accurately. The "scientific meeting" part has always been secondary. I've presented a number of papers at PittCon over the years (as a vendor), and always made sure they contained useful information and were geared toward a non-specialist audience. 
Attendance this year was just under 17,000; that's about half of the peak in the late 90's. Interestingly enough, the ratio of "conferees" (aka "customers") to exhibitors seemed to be a bit higher this year than in the past (historically, it's been near 50/50). I suspect that a big part of the decline is due to the availability of other venues (like this Forum, for example) for information exchange. 
I don't think the organization was any worse than it has been in the past (17,000 is still a *lot* of people!). If you want the "cutting" edge in a specific field, there are better meetings (ASMS for mass spec, the HPLC xx series for chromatography, for example). If you want a broad overview under one roof, then PittCon (in the US) or Analytica (in Europe). In fact, it has been suggested that PittCon should go to every other year, alternating with Analytica.