You will get all kinds of opinions about it but Accpac www.accpac.com (formerly SBT accounting) has a very large installed base.

TIW www.tiwcorp.com has a manufacturing system which also has a large install base.

Both of these have an install base of over 1000 installs.

Then there is a number of users for Web Connection www.west-wind.com

Alan Wyne
IS Manager
Rollpak Corp