Normally sleeve are more expensive, have a shorter lifespan and die suddenly, I also believe they are less resiliant to environmental effects such as heat. They have their advantages but if I was going to make prebuilt PCs I would use ball bearing.
Sleeves are quiet. That's the big reason. You never hear the motor or the fan spinning except for the air moving. They now last just as long as ball bearings. They used to have terrible life. They sound horrible when the do start dying though.
Hey again guys. Thanks for all the replies. My fan was faulty and I got it checked out, oiled and fixed. Now my cpu is running at about 50 degrees Celcius. Is that fine?
It's a **** lot better, now just make sure there isn't to much dust in the power supply, and that all other fans are working correctly... Also, what is the temp of the room that the computer is in? As that can cause a high temp also.