Pro MPA II : Excellent tube pre with lots of great features.

The main reason I bought this was for the Mid/Side matrix for recording drums and for the variable impedance feature. I'm pleased to say these work excellently as well as the Hi-Pass filter functionality. It sounds great and the overdrive is very cool, especially for blown-to-bits rock vocals but also a little bit of overdrive on a dark mic can be cool for metal guitars.

My only issue is when wanting to run it clean it can be a bit of a balancing act with the headroom, but then in those situations you probably shouldn't be using a tube pre. The only other problem is adjusting the M/S signal in relation to the headroom can be finicky, but I think that's just the nature of the beast.

Again, for the Mid/Side and Variable Impedance functionality this is easily the cheapest option and is of extremely high quality. Well worth the cash!