Merlin VSM and SETs?

I use the Art Audio Carissa Signatures with the Merlins, this is a higher current iteration of the Carissa, plenty of oomph for the Merlins! Marco points out the advantages of SET's well. The sonic presentation is totally holographic, palpable, I would add immediate as well, performers in the room with you. Bass can be slightly problematic with the wrong partnering equipment, but a proper tonal balance is quite easy to come by.
I have heard the Merlins with the Joule amps quite extensively, and I formerly used Cary SLM 100's with my Merlins. The Joules are nice, but I'm happy enough with the Carissa so as to not feel as if I'm missing something. The Cary's were a bit analytical with the Merlins.

Pabul, I can't compare the Joule amps directly to the Carissa as I didn't use the Joules in my system. I can say I prefer the Carissa in my setup to the Joules in the systems I've heard, I suspect my fully treated room had much to do with this. I much preferred the dimensionality, holographic presentation over the mostly untreated rooms of the Joule systems.
I can't imagine you would have any bass issues with the Joule LA 150, I use the Joule LA100MK.III and bass is just fine for me.
You will only know if an SET is better for you by trying it in your system, I can guarantee it will sound different than any push/pull or OTL amp.