You want an amp that can double power output from 8 to 4 ohms and similarly to the extent possible from 4 to 2 ohm. That is not likely to be a tube amp. Class D amps are very efficient allowing for smaller size and less power draw to do the job and the better ones designed with more robust power supplies are likely to do best.
Having said that, the 80w+ tube amps I heard sounded very good indeed with those but if it is the best performance one seeks beyond just good sound, particularly in the bass, more power and current is the ticket and Class D a very efficient, practical and potentially cost effective way to achieve that.
Having said that, the 80w+ tube amps I heard sounded very good indeed with those but if it is the best performance one seeks beyond just good sound, particularly in the bass, more power and current is the ticket and Class D a very efficient, practical and potentially cost effective way to achieve that.