I had the same issue choosing between M3TM and M5. Not having heard OB speakers, it was a tough decision. M3TM costs around $2000-2500 but it is an old technology - according to Clayton. I had M5 for about 2-3 wks and I have no regret. If any, M3 might have been better, but my listening room is too small for M3. The base is not an issue. In my setting, M5 goes to down to 32-34Hz. I am not sure of M3TM spec but I doubt it’s base is better than M5. After about 130-150hr of playing the speakers opened up nicely. The height of sound stage is one of the best I have ever heard. One note was it took me a day or so to get used to the look of OB speakers, but the wood finish is beautiful.