I'm a longtime 1911 owner/shooter, but I own other pistols chambered in .45 ACP.
Aside from an early KP90DC (stainless, decock-only P90), the only other metal .45's I own are a couple of S&W 3rd gen's (CS45 & original 4513TSW).
When it came time to consider owning a plastic .45, the only one that interested me enough to spend my own money on one was a M&P 45.
I didn't mind the USP45, G21 or even the briefly available SW9945 (I got to use one for a while that was on loan as a T&E gun). I just didn't like using them enough to spend my own money on one.
I rather liked the old P9S .45 I carried for a while, but it only had a little plastic. Parts availability and complexity of design (and lack of leather for off-duty use) eventually convinced me to get rid of it.
If I were going to start over, for full-size pistols I'd probably look closely at the Walther PPQ .45 and the M&P 45, and for a smaller one, the Shield 45. Maybe even a G36, as it has the most agreeable, slim and "short-ish" .45 grip frame, for me, among the Glock models.
Spending some rental range & trigger time with an assortment of them, using a variety of the type of .45 ammunition you would consider using, is probably a good way to begin research.
The increasingly stiff competition among makers of plastic pistols has started to flood the market with models.
None of them are going to be comparable (nor ought they be) to a nicely manufactured and assembled/fitted 1911, though.
FWIW, for a work-horse budget .45, which is admittedly out-of-production, the S&W M457 & M457S (stainless slide) were excellent, robust and reliable, no-frills traditional double action pistols (also referred to as DA/SA).