I too have had nothing but trouble with FM after Snow Leopard Upgrade
Running FMP Advances 10.0v3. Since upgrading about 10 days ago, ive had 112 "Filemaker unexpectedly quit" errors. All errors have been sent to Apple. DO they share them with Filemaker? I hope so. About 5 days ago, I grabbed the OSX 10.6.1 update from the Apple Dev Connect Site, hoping it would resolve the issues. It didnt. I tried a complete uninstall and reinstall of FM, and it seemed to help somewhat. At this point, I crash pretty much 100% of the time if I try and run a DDR report. I also crash more often when connected to a remote file served by FM Server Advanced 10.0v2. Outside of the DDR crashes, there is no common element around the crashes. Reading the lengthy crash reports generated by OS X, most seem to have snippets regarding Java, but this may mean nothing as Java seems to be part of everything these days and may just be coincidental. I hope this is resolved soon. FM has become virtually unusable, and our entire organization has ground to a halt while we figure this out.
I've no particular problems with snow leopard and FMP 10bv3 adavanced.
However, I'd suggest you to use Apple's Fontbook Validate Fonts feature, as I had problems (not fm related) with bad fonts.