@Ian @Nagraboy will have more current knowledge but I will give my perspective.
I retired to Portugal to live a low cost low maintenance lifestyle. So anything that maybe had maintenance requirements or a level of difficulty to get fixed was sold off. Also it gets hot here and I don’t like air conditioning. So power amp stages with valves doesn’t work from this perspective.
From a listening perspective I really like what valves do. I have bought a valve preamp with phono stage because I wanted that valve flavour again.
When I bought the Leben I also auditioned a hell of a lot of other amps from Unison Research, Pathos, Devialet, Nagra, Belcanto, Levardin etc. The Leben was the one that spoke to me most from a musical as well as design perspective. It has some useful features eg the whole amp acts as a headphone amp, output settings for speakers etc. it’s very compact and looks fantastic. And the designer only used quality mainstream parts.
From a sound perspective you either like the typical sound of these output valves or you don’t. I found that the sound was detailed enough but not as explicit as the Levardin (claimed to sound like a valve amp even though solid state) but it was a warmer sound with more tone. It had a rightness to it. It’s pacy sounding but not like a Naim. But it’s not going to have huge deep punch because of it’s topology. It’s going to work well with speakers like the SHL5 that don’t present a difficult load. I only listen at modest volumes so it was never a problem for me.
But amps are a personal thing. I would certainly recommend that you have a listen. If I was seeking a modestly priced valve integrated this and a Unison Research Preludio or Primaluna would be on my list. But if you are a headphone user then the Leben is the obvious choice. There again if you want to swap tubes frequently and use different types then Primaluna is the way to go.
Lastly make sure to listen with the speakers that you like as the Leben will only work well with sympathetic speakers.