I find that they all have thier quirks. If you do a little googling, you can find webistes that will track back to the hosting company from a url. That's an easy way to find out who is hosting sites simillar to yours.
If it really is a non-profit, you may be able to call them and get an opinion on the quality of service from their hosting company. A non-profit shouldn't have much if any reason to give you bad info.
Unfortunately, I've found that you can't really trust all these 'hosting review sites'... they all pretty much shill for thier 'parent company'.
I use arvixe.com. They're pretty good, and quite good value for Windows servers which is what I'm always after since I code in .Net.
My experience is, most sites have fans and detractors depending on their own experiences. And I often get the impression that the customers who really bitch have no idea whatsoever of how to install, configure or customise the code they've uploaded to the host, and then expect someone else to do it for $4 a month. And have no idea of the inherent limitations of cheap shared hosting that you're going to get anywhere.