I rarely sell a gun I like so of course have kept my 45s. One's a Colt Series 70 I bought new in 1976 and I definitely want to keep it!
Anyway, if you take your time and do an AR build maybe you can have both. I'd do a good milspec lower and research what uppers fit you applications best. Take a few months and save up.
I don't know a thing about slick guns but with so many sure things out there I wouldn't be in a hurry to get one.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek