Mark V sounds like a great deal in the future! I'd be very interested in such amp.
But from real world I'd pick Roadster or Roadking by Mesa. They are very similar and the only difference is that King has progressive linkage on the power section. Both are, In my opinion, very modern and versatile amps. I also think that their distorted channels are closer to DR than Mark. But those amps are rather set into heavy metal world. For Colin, I'd say Mark IV is really great deal.
As for Engl, it's indeed cheaper than Mesa...in Europe It's also very good amp, but if you like mesa sound why not to buy that one? Engl is Engl, Mesa is Mesa. It's more like dream comes true to me. I've always wanted Mesa and if I have the money I'll buy Mesa for sure. The same thing was about guitar. I've always wanted EBMM and now I have my precious JP07
I have owned Engls (Powerball and SE EL34) and the Mark IV (still have it). I really liked the Engls but love the Mark IV. No question my favorite amp I've owned/played. Let me know if you have any questions and I will do my best to answer them.
At the JP clinic here in Chicago last Tuesday he mentioned that he tried a prototype of the Mark V and liked it. That was the first I'd heard that they were working on a new Mark, but being a Mark IV owner, I was glad to hear it.
I used to buy combos and had both Lonestars, F-100, and the Stiletto Ace. I now own the Roadster Head and a Rectifier Traditional 212 Cab. My absolute favorite of the bunch. I may someday add another head for variety and would like to try the Mark V upon release. I think the head/cab is the way to go. The sound, portability and in the future just adding heads really works for me.
So far my favorite Boogie is the Mark IV.
I owned a Single Rectifier and a Mark III. The Mark IV is a great amp.
The only trouble is I always end up on the lead channel and never want to leave
The lead tone is *very* impressive and can do modern stuff as well. It's very tight as far as low end goes. It can be tricky to dial in when you first try one as each controls are very interactive.
Give the Rectifier series a try. Actually, give them all a try . I played a Dual Recto a couple weeks ago, and I found a great setting and cranked it. I was completely blown away. They're very versatile as well. I haven't tried anything from the Mark series yet, but hopefully when the Mark V comes out, the Guitar Center near me might get one in.