Many years ago I chose an Advantage (Bladelius) S250 over the Krell that I compared it with. All driven with BAT pre-amps. It was an excellent power amp which I subsequently upgraded to Bladelius Grendel and finally Bladelius Ymer. Each was a substantial improvement over its predecessor, particularly the Ymer. With over 4kw of power available the way it can grip and control a speaker is awesome. Bass has incredible drive and speed. At the same time it has a delicate touch, retaining texture and intimacy that can bring music alive in a very natural way. I hope that you enjoyed yours Neil!
I am very surprised that Bladelius has not marketed their products more strongly outside Sweden, so I'm afraid the Ymer is rarely available on the second hand market.