Tomorrow, Intuit will release QuickBooks 2012. There are alot of really big changes (FIFO inventory, Advanced Inventory Receiving, Lead Center, Cool New Pricing Levels).
Attached is a comparison chart showing all of the QuckBooks editions (PRO, PREMIER, ENTERPRISE) and all of the feature unlocks. Obviously, the larger editions will have more feature unlocks.
This is a major release and should be carefully evaluated to see if an upgrade will solve nagging problems (serial/lot tracking, automated pricing changes). Some of these new features may make a big difference in your business.