I owned Lamm M1.1's with my WP7's and they were amazing in the mids but the low low bass was missing or the mid bass was exaggerated. They are extremely musical. The give off tons of heat, the would heat my room 10 degree F in about 10 minutes. Not good when you live in the desert here in Phoenix, AZ. Plus when I sent them back for a checkup they only accept air so $1000 in shipping two crates was great fun!
I listened to the S400 on WP7's and WOW it's pretty amazing and suddenly my lamms sounded dark on the top end because of the air of the VTL's. My dealer had a pair of Theta Citadel (tall long monoblocks with tons of current) and I was asking about the S400 and eventually going to the Maxx's. He said that the S400 would run out of steam if I went with maxxes and that I should listen to the Theta (I already listened to the rowland 201,501,301's, 9t's modified). Wow suddenly I had the air of the VTL and amazing bass authority but with a more realistic midrange (I miss that warmth no matter how wrong it was for the presentation!) Theta has a 5 year warranty and the transformer (or other parts) are modulelar so they can be shipped back wtithout sending the whole amp. The VTL has that also, plus you can hook a computer to the VTL to see the hours on each tube..and the autobias is computer controlled (good or bad, since I work with computers a ton).
So I went with the Theta Citadels as the best compromise that allowed me to listen to limitless dynamics and the soft touch of depth and soundstage. Plus as an Added bonus they run idle 80watt so they are always hot, no more warmup for my system, just click and listen! I'm rediscovering my music collection.
The Lamm's only took 30-40 minutes for full warm up which is really short. I also owned Lamm M2.1 and i would probably gone M2.2's for the extra power, because my system completely opened up with dynamics after inserting the Theta Citadels in after having the Lamms.
Lamms are not fully balanced so save your money and use Single ended, the Theta is fully balanced and did benifit from using balanced connections.
Enjoy.
Chris