I have various centers, but the live centers I use the most are just the cheaper ones. They just have sealed bearings that are made in china, but they run true enough, and work pretty well for me. I don't usually have to worry about any major runout on that side of cue due to the centers being off when I use those. Mine see alot of use, because I use them for everything, so eventually a bit of play will take place as they wear over time, but By the time that happens they are usually scarred really bad, and tarnished up beyond any reasonable amount of cleaning, so in need of replacement for precise work anyhow. They are still good for repair, and general utility work after that though. One nice thing is they are really smooth, and I haven't had a problems with trash getting into the bearings, and tightening them up over time. They are only toss aways in My mind though, but for the price, I get more then My $'s worth out of them in the long run.
Greg