This is a very difficult question to answer. I have many cameras:
Canon F-1, Mamiya 6, Bronica S2, and an M2. In my opinion, the Leicas (I've also used M3s) are not easy to use. If you have not handled a Leica, you should try before buying. They are not as easy to hold as modern cameras, especially if you are used to some kind of thumb grip. Instead, my right hand feels cramped and tends to obscure the rangefinder window accidentally or pull on the self-timer. The viewfinders are small and difficult to see fully with glasses on. The lenses vary tremendously in how they handle. All Canon lenses handles the same, for instance, but each Leica lens is different and you have to get used to grabbing for the focus in a different place. And of course the biggest problem: film loading. It's not impossible, but it IS a pain. I can do it in about 40 seconds, but it takes practice, and you can't do it one-handed as you can with other modern open-back cameras. You'll have to sit and cradle it. Can you get used to it? Yes, but I've found I had to adjust to it.
However, no matter what other problems you have with it, once you press the shutter release, you'll be hooked.
One thing I've found to vastly improve the handling is to use a half-case, which helps for my 90, which is rather heavy. Does complicate loading, though.