What do you call a MEDIUM size nonprofit? How many individual donations a year/people in the database?
For a while, from about 1999-2007, I was doing some IT consulting almost exclusively with nonprofits, and worked extensively with Raiser's Edge. Raiser's Edge is a deeply entrenched product in a unique niche marketplace. It always seemed like most of the big nonprofits used it in some fashion, and all the really small nonprofits just get along with a weird excel spreadsheet.
(It does seem like an organization could donate to money to start a serious FOSS CRM system for small to medium nonprofits... it's a huge need)
Raiser's Edge is a resource hog and it seemed like nobody at Blackbaud cared about helping to make things faster. Back in the Sybase database versions, nobody realized you could put different database files on different HD's to speed up queries. We also once had a hefty support contract and were down over 25 days because they wouldn't/couldn't fix the database... eventually we needed to Fedex them a copy of the database, which they Fedex'd to Sybase, Sybase back to Blackbaud, and Blackbaud back to us. I asked: I drive by the Sybase headquarters in Emeryville every day, can I just drop it off to make it faster? Answer: No.
Queries and exports can be super slow: put one in at 10am... check after lunch. Make some changes and check just before going home.
Raiser's seems to be the best alternative in a very small pool of candidates, and you're most likely to hire people who have experience with it.