Art Audio Jota impessions

How do you feel about this model? Are the monoblock version significantly sonicly better? I have 100db Von Schweikerts and the synergy appears great. Does the Jota sound 4k better than the Carissa?
Are those speakers really 100 db efficient? If so, and if you don't have a really large room and/or listen at stadium rock levels, I would suggest you also listen to other Art Audio models. Do they still make the PX-25? That was my favorite Art Audio amp.