Keep the M&P (again)
I can tell you my experience, for what it's worth. I've got decades of revolver time behind me, when I was all but forced to carry an M&P.40. Can't say it was love at first sight, but pretty close. I'd learned to hate Glocks, and thought this was a fancy Glock.
That M&P opened my eyes a bit, and I started exploring, and soon became interested in 1911's. In the mean-time, I got a compact M&P to go with the fs, and I carry it just about all the time.
Now, to the 1911. I "love" them. And can't believe I didn't discover them before. But, its a different weapon, and I'd bet you money that it cannot replace your M&P, at least not immediately. If I take time and place my shots, I can shoot considerably better with a government or commander than I can with my M&P (not so with an officer or smaller). But that's only if I take my time. In competition, time to first shot, and speed-shooting groups, I am simply faster "and" a better shot with the M&P compact: which is way lighter, way smaller (generally), and has way more capacity, and is probably way more reliable.
That last might need negotiating. I have two 1911's (Kimber fsss & lwc) that are reliable. They both have thousands of rounds through them without issues. But it took me some head-scratching and parts-changing (not to mention dollars!) to get them there. Both of my M&P's have thousands of rounds through them without so much as a hiccup, just boringly reliable (at a fraction of the cost).
I could sell the M&P's now that I have two "proven" 1911's, but I wouldn't. I'm still faster with my compact, and it still holds more. But you're certainly correct: if you want a 1911, you should have one! It's a privelege! Just don't trade for it, wait to sell your M&P until you're convinced that you don't need it any more.