Best alternative lower for Colt M4 Upper?

[JIMDICE]

I see Colt M4 style uppers at Shows from time to time and I now have the opportunity to trade for one.

I was curious though, rather than dropping some serious bucks on a new Colt lower, is there a particular company's lower that is a 'perfect fit' for Colt uppers? I'm not quite up to par with the new manufacturers and would love to hear everyone's opinions.

thx.

jimbo.

 

[Claven2]

Any in-spec lower will work as well as any other, assuming the Colt is a milspec pin model.