You mentioned that these sound close to SET amps. What amps have you compared them to?
I've directly compared them to my Quicksilver 300B SET monos and Wright's own WPA3.5 SET amps that utilize the same 2A3 tubes but solo, in a SET topology. The Mono 10's have some qualities of both...they do a wonderful job of that airiness and holography that bring a breathy presence to the SET amps, but, at the expense of perhaps the last word in those qualities, the Mono 10's bring a bit more muscle and boogie-factor into the equation. They do a better job with more dynamic, layered music (orchestral, for example) than the two SET amps I've owned can. They're still relatively low powered at around 11 watts. The lows are a bit tighter and lower than either of the SET amps could muster. The SET's put all their eggs in the midrange basket, but boy do they do that right. The 300B's are a bit more versatile than the 2A3 SET amps in my experience with the two amps I've mentioned, but be aware that system synergy is a make-it or break-it proposition here. YMMV according to what you choose and what you try to match it up with. I would say the Mono-10's require similar care in choosing the right speaker (ie sensitive speaker) for your room/musical tastes, as would a SET, but they would probably be just a bit more versatile in that regard. I'm sure I've written about this before, so you can search the archives. Of course read what others have to say, listen to examples for yourself, and make your own call. It may not be your cup of tea, but if it is you will be very happy to have found that out because it's like nothing else out there. OTL is also quite a unique sounding alternative. I don't have enough experience there to give you any input, other than I think it's worth considering too, as someone has already suggested. In that realm read some of the posts by member TWL (Tom Lyons) for further input. I don't think he's posting here anymore (sadly) but the archive should have plenty of his input on OTL amps.
Hope that helps.