I've favored Tech 21 units for all my direct recording and performing.
The Sans Amp Classic is an amazing unit! Hard to distinguish it from a real amp when tracking. Add the Boost D.L.A. pedal and you have an amazing pro guitar rig that weighs less than 2 pounds!
When I do need to amplify piezo signals or want to add a cab to the Classic I use the Power Engine. Great stuff.
Check them out at tech21nyc.com.