I mean I train MMA.
They teach us striking, takedowns and ground game.
We do not wear GI, we just use MMA gloves.
Probably it would be better to train only Muay Thai for some years in order to get very good in the stand up, and then spend some years training BJJ or Wrestling for the ground, and only theeeen begin training MMA.
However I like a lot MMA, I enjoy a lot the trainings, and when we spar with MMA rules I like knowing that if someone is owning me in the standup, I can go for a takedown and maybe in the ground I will be more succesful.
Being said that I feel much comfortable in the stand up than in the ground, I have long arms so I have reach advantage almost over everybody in my GYM and I trained some boxing in the past so it obviously helps a lot.
In the ground though....I have tons of work to do there.