My Colt Series '70 Gold Cup outfitted with a Briley bushing out shoots my 945, but not by much. If you do a search for the other threads about the 945, there does seem to be one common trait mentioned, they are fussy eaters when it comes to finding which ammo will perform the best with them.
As previously mentioned, there's not much aftermarket stuff available, but there is one item that I really liked.
Speed Shooter Specialties sells replacement grips for the 945 made by Hogue (who also makes the ones that come with it). Each grip panel is 1/16" thicker, adding 1/8" total to the width. Now that doesn't seem like it's enough to make much of a difference, but for me, it made my 945 feel and handle a heck of a lot better.
Is the price of a 945 worth it? That's a tough call, with the proliferation of factory "loaded" 1911's available, it's more difficult to choose.
One of the things I like about the 945 is, if nothing else it's unique... it's a "hybrid", the upper is basically a tricked out 4506 slide, mounted on a 1911 style lower.