Is it a good time to switch to Boost or should I wait until ATT buys off the spectrum?

I'm on T-Mobile and they hiked up my price to $60. I'm skeptical of Boost because of the many negative reviews.

I like their $10 promo for two months and then forever $25 but I could also go with Metro by T-Mobile and they offer a $25 promo for BYOD.

What I do know is I'd prefer to stick to a ATT or T-Mobile network. Verizon isn't so good in my area.

My other question is how do I know which SIM I get? I've heard there are three types, one for ATT, T-Mobile and DISH.

Should I try Boost when it's ATT and T-Mobile only?