Not terrific. You may end up turning the necks on Lapua and Norma cases for what ever shooting discipline you're into... but you'll typically be removing a few tenths instead of the .001" - .003" I've found on some lots of Winchester cases.
Saying that, I got a lot of Winchester cases about 5 years ago that were so consistent and concentric... it was really hard to believe they were Winchester.
I'm sure you know this, but the issue is the difference between the chamber neck dimension and the loaded case neck. If you have to turn off a lot of brass to get concentricity, then you have a lot of needless case neck brass expansion... which really reduces the effective reloadable life of a cartridge case, unless you think regular annealing is great fun.
If you've never tried them, you owe it to yourself, at least once, to try Lapua and/or Norma cases.
Cheers,
C