I have the MM in the classic monogram with reverse and I also have it in the géant print.
Regarding the first one, I completely agree with the above posters, so I really do not have much to add, except that:
1) I am not fully used to carrying such a “small” bag as a day to day bag (and mine is in the bigger size), so I always end up putting more stuff than I should and it gets a funky shape at the very top. Also, when it is über full, the clasp closes in a weird way; let’s say halfway, but the flap will not open because the magnet is really strong, as SympathyDuet and leooh have mentioned.
2) The MM can get a bit heavy (at least for its size, IMO) with the chain and its clasps sometimes get momentarily stuck with the strap’s clasps, especially when you lift it by the strap. The chain also (sometimes) gets kind of stuck on the gussets for a second as well depending on how it moves. I really like how it looks though, so I leave it on anyway.
3) I normally use the Cosmetic Pouch PM and it will not fit comfortably, but the middle zipped compartment fits everything that I normally put into the pouch. For a wallet, I use a Zippy Coin Purse and it fits like it was made for this bag.
4) I thought the leather tab would be full of scratches and stains by now — I took it with me to Hong Kong and it travelled on the subway and got rubbed against people and things, but it is pristine. This leather is not a bit similar to VVN.
5) When I saw it on the runway for the first time, I flat out hated it, but it is definitely one of the coolest bags that I own. Visually, I love every angle of it. And strangely for monogram, it looks super elegant and not flashy at all. Needless to say I only like monogram in very few pieces/styles, so I guess that says a lot.
6) You can also use the bag as a clutch, so I guess that you could say it is a three-in-one (“three” if you consider you can carry it crossbody).
The géant one is pretty much the same, although I have not used it yet (hate the print, but got it as a gift). The silver hardware and the shiny crinkled black leather look amazing, if that helps in any way.
ETA: I really like the Céline Box; however, something else beside the leather stopped me from pulling the trigger. Then, after I got my first Dauphine at the end of last year, the Céline Triomphe and the Dior 30 Montaigne really caught my eye, but if I had to choose between these, I would still choose the Dauphine and I am actually hoping for a different combination in taurillon or for an épi version to come out.