I have the 2 1x12s that i've been using side by side with the mod50 for at home and they do sound really good, but I really like the TM 2x12. It just sounds bigger and "more open" to me. I'm awful at describing sounds... If you're near a guitar center see if you can ask them to try it out. If you can't get a good listen at the store, you could always buy the 2x12 and then use their 30 or 45 day return so you can give it a good test with your rig.
In my opinion, and many others who have played it, you really can't go wrong with the TM 2x12. I'm looking to pick one up too, and maybe then use the 1x12s for wet sounds or stereo. If you liked the 2 1x12s, I think you'll really like the TM 2x12.