A fifth option, which is the one I'd take, is to buy the new Bryston B100-SST. Read the recent review on the B-100 in HiFi+ magazine for detailed information.
Intergrateds: Bryston,Creek,Naim,Musical Fidelity
Looking at B-60,5350,nait 5i, MF x-150...any thoughts on which one would work best with 4ohm load...looking for lively, transparent, detailed sound...thanks...