I just bought a mk.III 22/45.
A couple of points:
The mag disconnect is kind of a pain. It makes it harder to get the mags properly seated and prevents them from dropping free. I plan on removing it.
The target barrel plus the polymer frame does make it a bit front heavy. I prefer the 1911 style grip angle but the all metal "luger" style grip while heavier overall is more balanced IMO. I haven't held a "lite" version but I imagine it would be better balanced and lighter overall.
The loaded chamber indicator, in addition to being ugly, makes cleaning the chamber a bit of a pain. I haven't experienced it causing and feeding or ejecting issues but I have only run a couple hundred rounds through it.
There are 2 versions of the 22/45, one with molded grips and one that has removable grips. I would try and get the one with removable grips, unfortunately there where none available at the time. I have seen some kits to add grip panels to the molded one but you have to drill into the existing frame. I did not mind the feel of the molded grips so I just got that one.
I got it for $270 at a LGS new.