Harbeth SHL 5 amplification

As I said in my response to your previous post, you need to demo the speakers at home with your equipment.  Or at least bring your amp to the dealer.  That said, if you are looking for "power" the SHL5s will sound better, IMO with a robust amplifier. I had very good results with my Naim 250, which only had about 70 wpc, but with a heavy power supply.  Then again, you may love the sound with your Leben.  I understand that people want to gather opinions as well, but the only way to know is to demo.  If you are working with a dealer, use his services and demo the setup.  If not, just buy used and hope for the best.  Trust your ears.  

I think what is almost uniformly left out of these type of discussions are the listener's musical preferences and expectations.  If all one listens to is string quartets, solo guitar and other small-scale works, a low-powered tube amp may be absolutely fine.  But if one expects a significant amount of "bass and power" as Arthur Salvatore says, you need a larger amplifier.