I've got a couple of the Kimber KimPro Tac mags that I picked up from
http://www.the-armory.com/shopsite_sc/store/html/page64.html
They're halfway down the page, they sell them for $18 and every other site I've been to they're no less than $25. I've put a few hundred rounds collectively though the three I've got and haven't had any failures of any kind.
Whatever you buy, just make sure to order mags that are made for an aluminum frame gun. Standard mags can ding the feed ramp when loading the last round because the follower can nose dive forward and hit it. The mags I linked above don't do this.
I carry Wilsons because they have the low prifile steel base option. I use Tripp and Kimber Tac Pro at the range. I have used ACT mags, too. All work, but the ACT mags are bottom of the bunch. I find the Tripps the best of the bunch, but the baseplate is large. The Kimber Tac Pro mags are excellent, too, and are 7rds with a flush tapped steel floorplate.
The Kimpro Tac mags are all I use in my Ultra Carry II. My first UCII was 100% reliable with the Kimpro Tac mags and I then decided to try some Wilson Combat officer mags that did nothing but induce problems, went back with the Kimpros and no more problems. I sold the first UCII for financial reasons and bought another last year because I liked it so much. Again I've used nothing but the KimPros with zero malfunctions.
First time I realized the WC mags are not always the solution and could actually end up being a problem. What I would do is buy a mag or two of the type your most interested in and run them for a bit to make sure your gun likes it before you go buying a dozen or so.
