It has happened several times that I've spent my allowance on a much anticipated upgrade only to get it home and find that it's incompatible with my existing system. It seems that often the manufacturer was aware of the shortcoming but didn't warn of the problem in advance. I don't want to start a flame war, but rather, a simple listing of those things never listed in the small print. It would help people who are still collecting new, and old, stuff.
My example: the A570 (boot from a CD like a CDTV) is a cool upgrade for an unexpanded A500, but it can't take acceleration. It works for a month or so and then gets flakey and finally refuses to boot. I tryed it with AdSpeed and Supra's 28Mhz accelerator with the same result. The A570 is compatible with Supra's 500RX ram expansion and Amitrix hard drive expansion.