I've used UMC extensively in 10MM auto, .40, and 9MM, as well as .303 Brit and .223. I've been very pleased with the results.
Perhaps they are seconds, but I haven't noticed any difference in the number of times the cases can be reloaded as compared to standard bulk Remington brass.
For my money, it's about as good as you can get in bargain ammo.
I've also used a ton of Wolf with no problems whatsoever.