I just downloaded the Mesa Dual Rectifier and Mark IV profile packs, and they're absolutely fantastic. There are a few amps that are capable of great tones, but really hard to dial in. Boogies and Bogners, in my experience, and a lot of the profiles of these amps on the Rig Exchange are just 'not quite right'. Not the case here, at all. The Dual Rec profiles are exactly what I wanted them to be: tight and dynamic. Add some delay and reverb, and you get those searing, articulate, liquid lead tones that sound so good. The Mark IV tones are properly dynamic, and showcase the versatility that the Mark IV is famous for, in a really natural way that sits perfectly in a mix.
One thing I've noticed in my Kemper ownership is that profiles that respond properly to rolling off the volume are hard to come by. Some of the factory profiles do a nice job (the Fender Blackface being a good example), but most of the time, when you roll off the guitar volume, the sound just gets woolly. In this case, the sound desaturates and remains clear just like a good tube amp is supposed to.
I'm not affiliated with Cililab in any way. I heard a free profile on the Kemper Facebook page, went to their site, browsed the audio clips of their profiles, fell in love with the MB tones, bought them, and felt compelled to give a public thumbs up.
I'm not proud of this, because I put my Dream Theater phase behind me, but these profiles have got me going back to Images and Words. That's the most negative thing I have to say about the profile packs. You exposed me to James LaBrie again. Bastard. 