If you expect to cut molding with it, get a compound miter saw rather then just a miter saw.
What do you expect to do with this saw? If it's just cutting 2x4 for a basement remodel, then just about anything on the market will be adequate. For bigger stock get a 12"
If you expect to do any more precise woodwork like making picture frames, etc. You'll want a better saw. One thing to look for is to make sure that the left & right fences are either a. already aligned, or better b. can be adjusted independently so you can align them again after it takes a couple of wacks with a 2x4.
On this count, I found Craftsman & DeWalt to be crap. Or at least they were a few years ago. I had a Craftsman, and couldn't figure out wy my miters weren't accurate until I checked this with a straightedge. Was within warrenty, so I took it back. Took awhile to convince the guy there was a problem, but they finally agreed to get a new fence. This was crooked also, so they gave me a credit for a new one. So I showed up at Sears with my straightedge, and not a single display unit was true! But they had a Makita that could be adjusted. So I got the Makita, and it's done great for me.
As for radial arm saws ... I hate those SOBs Give me a table saw any day. Can't keep em true & ripping hardwood is an impalement waiting to happen. But if you have to get a RAS, I'd reccomend an old Craftsman or Delta. The big heavy ones with cast iron everywhere. The new ones are all sheet metal, and don't take the abuse as well. Plus you can often find those old craftsman saws for < $100