I saw both new MUT and Grand MUT...
Several times the protos, and lmately the production watches.
I can tell you that both are gorgeous.
I like a lot the dial of the Grande MUT, with its sunning elegance, and perfect symmetry.
The small second is verty fine, and this watch " smells " Quality ".
But, as Clavi and other said here, it is not anymore an Ultra Thin, but a Thin watch.
If I have to compare both movements, I mean the MUT Manual and the Grande MUT Automatic, I'd say that I prefer the MUT Manual, for its better finish.
It is my own preference, indeed, but at the end, it's up to you to decide, and in both cases, you won't go wrong with these 2 Beauties.
Hope this will help you in your decision.
Please, let us know the way you're thinking, and your final decision!
Best.
Nicolas