I've got a few sets of BST wheels with ceramic bearings...can't say I noticed any difference but that lighter wallet should make you marginally faster!
They are supposed to roll more freely and should last just about forever...you can find a video or two on Brock's Performance where they bang the actual balls, steel, cheap ceramic and Worldwide Bearing balls, with a huge hammer and the results are pretty impressive. The WW ceramics didn't deform and actually left divots in the hammer and anvil.