I don't own the 1+, but looking at the pics and specs, the 1+ are shaped more like the M 1, but have tech like the MT. They have the clicky buttons instead of the touch found on the MT. They have ANC where the MT has "hear through" mode. These also fit more like IEMs than the MT which basically sit ON your ear canal, rather that insert into them. They both use the same app AFAIK?!
If you like really deep sub-bass, these might not be for you, as they only go down to 100Hz (according to the specs). But they last for something like 9 hours one charge, and 45 with the case... Other than those things, I don't know the differences in sound, or the quality of the ANC, etc...
Edit: My bad, they do not have ANC, it has noise cancellation of the mics (apparently for when you are on calls)...