Do not role your own solution. You're effectively crippling your org once you leave. Which will eventually happen.
I've done IT for small non-profits. Used both Access, FileMaker Pro. The third party apps targeting non profits range from okay to terrible. Biggest challenge is customizations and forward porting that crap. No different than orgs which customized bugzilla and then had rework when a new bugzilla comes out.
What we're doing now is moving to SalesForce. It's free for small non-profits.
I'll let you know how it works out.
I'm ambivalent about features and so forth. But hopefully the larger community of SalesForce talent will make future continuity easier.
One big win will be the ecosystem of add-ons. My current org is excited about using the CRM features to improve engagement with clients and donors. The kind of crap I really don't want to write myself, yet again.