Kerry Irons is right: it's not worth the money unless it's a school woodshop project or you're s stubborn, cheap, Yankee-like me!
What to look for: I wouldn't ride plastic rollers; they tend to develop static charges which lead to nasty sparks when you climb off the rollers-they're painful! I recommend the 3" diameter rollers because the smaller rollers offer a measure of resistance which is sufficient for most cyclists and builds a measure of power. The common, larger 4.5" diameter rollers will have most cyclists near their top gear after a few sessions.
The plastic end caps of Kreitler rollers are the exception; Kreitler is the legendary name and you can trust any of their products. Seriously consider watching eBay for the 3" models; they were formerly called the DynoLyte or PolyLyte for the plastic end cap version. I see them on auction many times a season.
If you want to buy new, I recommend the Kreitler Compact 3.0 because they sit lower to the floor. Consider whether you need the ability to fold the rollers for transport or storage. Kreitlers are whisper quiet and smooth. I've had exception customer service from Kreitler. They last a lifetime with only occasional belt replacement and I consider the prices extremely reasonable.
The little bumper rollers you describe are hardly necessary. There's a learning curve, but it's brief. And even when you fall off rollers, there's sufficient seconds to unclip and put a foot down. Contrary to popular belief, you won't take off like a rocket. Be sure and put a mat under the rollers if you ride on a carpeted floor because you will burn a hole in the rug if you fall off, not to mention dripping sweat.
And don't forget to wipe off your frame with a wet rag after sweaty sessions, as I do. Sweat leads to rust, particularly with steel frames.
For a comprehensive comparison of rollers, read this report
here.
The TruTrainer and eMotion rollers mentioned also have detailed reviews on the site. These two brands are the Cadillac of rollers but quite expensive and usually not the first pair of rollers someone buys. To see how each brand works in real world conditions, do a youtube.com search by the respective brand.