I've been using them for a few months now. Had good results during hunting season (a buck and a doe). No complaints really, other than cleaning them sorta stinks without an ultrasonic cleaner.
I saw no difference in accuracy between those and the Remington 209ML primers, but the Variflames are definitely cleaner when using Trip-7. (I'm currently shooting Trip-7 FFg.)
I've tried small pistol and rifle primers in the Variflame without a hangfire. Think I'm going to try the magnum small rifle primers next, just to try them.
As far as cleaning them, you can use a primer pocket brush like the mfg recommends. I don't have one, but I do have a small ultrasonic cleaner I use to clean breech plugs and other gun parts (as well as the wife's jewelry -- a definite plus). I put the Variflames in a baby food jar with a little nitro solvent and put the jar in the sonic cleaner. Works great, but they do come out a little discolored. HTH