I haven't shot the Citadel, but the local gunsmith was telling me he bought one for the truck/carry and really like his.
I do have a Taurus PT1911 I bought used for $450, looking on gunsamerica.com looks like they can be had new for around $600 as well. I really like mine, never had any problems. Probably ran 1K rounds through it so far, don't know what the round count was before I got it.
Though many may come from the same factory, I'd probably go with a Rock Island Tactical. They tend to get good reviews by the owners and good CS. There were a couple at Precision Firearms that could be rented. I tried one and was pleased with it for what it was.
I have a Citadel full size. It is absolutely fantastic. I looked at them RIA but the citadel just felt better. It also has a few advantages. One being the front sight is dovetailed in and not fixed. Trust me you won't be disappointed. The only thing it doesn't have is the colt or Springfield name. Other than that it is a great 1911.
I would've bought a taurus, until I got offered a really high end 1911 in trade for a rifle, I no longer wanted. They're available off and on, from larrys pistol and pawn, for 450. After shipping and transfer fees, thats right around 510.