1) Back up.  Yeah, I think I would back up anything run in Intuit software. 

2) "Our"?  Is that like the A team?  

3) "Pro and Premier data files start to take a long time to run reports at the 150-200 MB size"

I'm guessing that is an understatement; you are being too kind. 

4) " In addition, Pro and Premier become more susceptible to data corruption and other funky issues,  

(Nooooo. Really?) at the 150-200 MB size".  Hmmmmm.  Could that have anything to do with Intuit's unusual file (db) design? 

Seriously,  I can write an accounting program with Alpha Five running under XP mode in Windows 7 that is more stable than QB.  And, I had used a simple Lotus 1-2-3 (with Harvard Graphics just for some pazaz) to do payroll taxes that is was more accurate than the $500 per year Intuit subscription I now have.  AND, when I need tech support I don't have to consult the rooster in the kitchen.