Finally a valve subject again!
But.... there's nothing new! Valves sound gorgeous if you like their sound. I do!
Valves give more stage-depth, stage-width, sound fluently, and especially with voices, - very exciting. In total to me they sound captivating. Not even an expensive ss amp comes close in these charactristics!
But valves give less 'slam' especially in the bass department.
High efficiency - and easy load speakers help to get the best out of valves, and can give you good bass, but it will never give you the 'slam' from even cheap solid state! If a valve-amp sounds good in the 'slam department', i think it will sound less good in the beatiful valve characteristics.
So it all depends on your taste for sound! And yes, in any case (SS or Valve, or hybrid) you have to spend some serious money!