2 Strokes
I have used wiseco prox and vertex in CR500's all worked better (lasted longer) than cast stock items.
The last was from England I'm sure it was Vertex and it had a black high wear coating on it. It lasted a few years with just ring changes, every time I put a Micrometer on it it showed minimal wear (My Barrell was heavily ported and tended to eat pistons)
ProX make coated ones as well I believe. So you pay more initally but they last longer and in the end are more cost effective.
No Idea about 4 stroke biscuits, they probably just wear out