I protest against the lack of inclusion of Presbyterianism.
No one's converting to mainstream Protestantism anyway.
This is sort of hard to answer. I can judge religions by their matching to my personal views, but if I'd have to think differently to subscribe to a religion, so the question is essentially moot.
First, there are fast growing conservative Presbyterian churches. See
www.pcanet.org and
www.opc.org . There's more to Presbyterianism than the pseudo-church PC(USA). Second, even if presbyterianism was just "Mainstream" protestantism, Methodism was included, and that one doesn't even have any conservative denominations.