GuitarG,
Actually, MAS 200 comes in 2 versions. MAS 200 based on Providex, and MAS 200 SQL which uses SQL Server as the database engine. We have several clients with 20 to 30 very active users running on MAS 90. The largest of these processes 200 to 300 invoices per day. Their customer master has over 130,000 customers. They are running on a two year old Pentium server and P2 and P3 workstations.
The main reason to go to Mas 200 (non-sql version) would be if you expect to quickly exceed the 20 to 30 user range. I think "Best" says 10 users in their white paper, which could be a CYA statement or maybe because MAS 200 is quite a bit more expensive. One other benefit of MAS 200 (non-sql) is that updates (batch postings) occur faster. By faster, I mean a few seconds for a daily sales update versus maybe a minute with MAs 90.
MAS 200 SQL actually seems a bit slower in terms of user interface with slightly slower response when a user, for example, moves from a Sales Order Header to the lines page.
The big difference is when you print reports. They scream! Printing an AR aging with several thousand customers takes seconds compared to minutes on non-sql versions. Of course another reason might be the existence of an SQL based application in your organization that you are hoping to link to MAS 90 or 200. ODBC does this, just not as fast, and with less flexibility.
The final reason, if you can call it that, is someone in your organization that falls for the "Industry-Standard" hype. For some reason, there are those that feel SQL is the only way to go even though they have never worked with SQL, ODBC, DBF, etc. They also are probably not the person writing the check. Going from MAS90 to MAS200 will cost you about 5K additional for the first 5 users and a couple k additional for each 5 user pack after that. SQL is that much more than standard MAS 200.
Whatever you consider, keep in mind that Best will give you 20% right off the top if you are a registered Peachtree user. Hope this helps.