I've shot a friend's M96, which had a very nice trigger and was quite accurate and pleasant to shoot - I just couldn't justify the high price tag, and the heavy weight, in a .223 carbine.
I know of a couple of guys with Daewoos, and they say their rifles shoot very accurately - nowadays it's getting a little hard to find 'em, and those who're selling their Daewoos are wanting as much for them as a good post-ban AR. Also, I don't care for the 180-degree arc from SAFE to FIRE on the Daewoo's safety.
The Kel-Tec SU-16 seems like a neat idea, being VERY lightweight and inexpensive, but I'd rather they made the thing with a metal front sight post instead of the day-glo orange plastic front sight they're using. The magazine-storage well in the stock is an excellent feature, as is the Picatinny-rail on top of the receiver. The folding/takedown feature is pretty neat, but it SEEMS like it makes the rifle more complicated/fragile. If I can see my way clear to acquire one next year, I'll probably have GG&G install their folding AR15 back-up iron sights on the thing in place of the plastic sights, and maybe screw on a Vortex flash-hider to boot.
I've owned an Armalite AR180B since October 2002, and I'm VERY happy with it - it runs like a champ as long as you use good mags, and I've been able to keep an 8" steel plate dancing at 200yds with it. It only weighs 6lbs, and it gets on target right quickly for snap-shots, and it handles very well on multiple targets in three-gun matches. I've personally installed Trijicon sights and a Rock River Arms match trigger on mine, and I'm quite pleased with the results. Some people(NOT ME) think the AR180B feels flimsy because of the polymer construction, and it's recoil feels somewhat brisker than other, heavier .223 rifles, even with the LOUD muzzle-brake integral to the barrel. If only Armalite would put a Picatinny rail on the top of the receiver and a manual bolt-release lever on the left side of the rifle, it would be close to perfect.
Although they have nothing in common with AR15's, you might want to consider a Kalashnikov-pattern .223 rifle like the Robinson Arms VEPR's, the .223 Saiga, or the Romanian SAR-3 - their reliability and durability are near-legendary, and they should be at least a couple hundred dollars less than most AR's. The only downsides with these rifles are their sights and safety, which aren't as user-friendly as those on an AR, and decent, reliable 30-rd magazines can sometimes be hard to find for the .223 AK's - although if/when you DO find them, they're usually still reasonably priced.