I am only using Mac for BlitzMax since I don't have Windows or Linux and have not had any problems at all. It runs very well, the OpenGL is great, and everything has been nice and smooth. I think maybe your issues are Linux only. Linux is the smallest user-base (i am guessing) and therefore perhaps hasn't received as much attention that would lead to discovering bugs and such. But I'm sure BRL does their best to make sure it all works correctly after all there'd be little point supporting the platform in a half-baked way, it'd have to be all or nothing since there is quite a bit of work involved.
I have compiled stuff on Windows on other computers and found my BlitzMax code to, for the most part, work first time without any changes needed. I only found I needed to make changes where I had some code that referred to windows-only API stuff. I know the Mac forum isn't much more active than the Linux one but there are people developing for Mac, it's on the increase.
I always have my eye out for PPC Mac demos/games that people post here. I haven't collected that many so far but there's a few.
I have compiled stuff on Windows on other computers and found my BlitzMax code to, for the most part, work first time without any changes needed. I only found I needed to make changes where I had some code that referred to windows-only API stuff. I know the Mac forum isn't much more active than the Linux one but there are people developing for Mac, it's on the increase.
I always have my eye out for PPC Mac demos/games that people post here. I haven't collected that many so far but there's a few.