ASI, Blackbaud, IRIS, ThankQ and so on. Or indeed, if you peruse internet discussion boards, then to and from CRM systems such as Microsoft CRM, Salesforce and SugarCRM. As such, you might therefore wonder why someone is no longer using the very package which you were considering buying.
My message is: don't necessarily worry, find out more about each such situation and don't lose sight of the more important factors in any database implementation: the data, the people and your business processes.
Of course, if you find patterns of desertion from one system then that could be an issue (and there are indeed one or two suppliers who I would be more concerned about if you told me you were buying their software now), and if you do find no-one who can give you good feedback about supplier X then that should at least make you think twice.
Equally, there could be good reasons for a charity to move to a new supplier: their 'old' database might not be appropriate for them anymore (e.g. they could have grown out of it, changed technology platform); in-house skill-sets may have changed; the supplier's costs might have escalated significantly; the supplier may have been selling, or now be selling multiple systems and therefore have dropped support for one database. Or the 'old' supplier might not be providing perceived value anymore, might not be releasing new versions, might have cut-back severely on support.
But all too often a new system is purchased for reasons not truly central to the database software itself: a new senior manager might arrive at a charity and prefer database X; there could be loss of faith in the 'old' database when in actual fact it was more down to the poor data, lack of training, lack of investment, a great database manager leaving and not being replaced etc etc; there could be a misunderstanding or lack of knowledge about the capabilities of the old database; an out-of-date version might be being used; or a charity's IT infrastructure might be so poor that the old database is running so slowly that any modern database would struggle…
And with the more successful database suppliers, if even a small percentage of their clients are unhappy, then that will be more visible to the market compared to a smaller supplier who might only have one or two users jump ship over time.
So consider carefully if you hear about a charity moving between fundraising systems and you are thinking about buying the database which that charity just dropped. Try to understand why that charity replaced their old system, who was involved with that decision, how long ago - what they learned from the process. Talk to as many such other charities as you can and get a broader picture. And remember that whatever system you buy, the software is still only one part of the success of that new database.