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Wilson, Tripp, maybe McCormick.
I'm seeing more Dawsons since the Dawson Ice magwell is becoming popular and one version of it almost requires the special Dawson basepads (which are available for Wilson mags as well as some others). People using the Dawson mags seem to be making positive reports on them. I actually got to try one, with the Ice magwell, on a 9mm 1911 Saturday. I only fired one mag, but it seemed very well made. (I mostly just wanted to try that magwell, since it was the first one I'd seen in person. But he insisted that I try shooting the gun. Hey, I'm always willing to shoot, especially if it's someone else's ammo Competitive shooters are the greatest about letting others try their gear. ) The guy who owned the gun used those mags for the whole match, probably 150 rounds or so, and I don't remember him having any trouble at all. Dawson mags are also available with a more "standard" basepad as well, of course.

Other brands, forget them.

USPSA has the same 43 ounce limit for Singlestack Division. I haven't heard anyone say theirs was too heavy, but I know some were worried about it. From what I'm hearing, it sounds like the Smith & Alexander magwell is actually a little heavier than some of the big, gaping magwells like the Dawson Ice, the SV, or the TechWell because the S&A is steel while these others are aluminum. (I don't know which of those are or are not legal in IDPA. I know they all fit in the box, but on some, you need extended base pads on the magazines to seat the mags quicly and securely. Some of the extended base pads have to be ground off just a touch in the front to fit in the box.)
The S&A seems to make weight in the .45. But I have a sneaking suspicion that the 9mm may weigh a hair more than the .45. Everything else being equal, the outside of the barrel is the same diameter, but the hole down the barrel is smaller, meaning the walls are thicker, meaning more metal, more weight. I have heard of people changing out parts to lighter weight components to make weight. But I have not heard anyone say "With this, that, and the other, it weighed this much. But when I swapped these out for aluminum/titanium/carbon fiber parts, it weighed this much."

I shoot USPSA (not all that well, but I go and shoot and have fun). My next pistol will probably be a 9mm Spartan.
Go to the forums at brianenos.com, which is THE forum for competitive practical pistol. Do a search for "Spartan." I got about 15 pages of thread listings. Search just the 1911-style Pistols forum there for the word "Spartan," and you can cut that down to about 5 pages of thread listings. Most who've tried 'em, love 'em.

EDIT: By the way, I'm a bit of a Kimber nut. I only have one Kimber, an Ultra CDP II, but I get every catalog, keep track of website changes, wear out the catalogs referencing back to them all the time, know the differences (not just looks) between one model and another. There are several more Kimber 1911s and at least a couple of their rifles up near the top of my wish list.
So to say my next pistol will be a 1911 that is not a Kimber, says a lot about the STI Spartan.