I have a STM high speed wet tumbler and love it, but this method can peen your case mouths. The fix for this is to trim the cases after wet tumbling and remove any peening.
Below on the left is my fault for falling asleep and tumbling too long, the case on the right is brand new right out of the Winchester bag.
The case on the left was fired twice and then wet tumbled, before tumbling the case mouth had been trimmed flat and deburred.
So yes wet tumbling will pound your case mouths, and to help prevent this do "NOT" overload the tumbler and keep tumble times to minimum.
And if you can't see the peening then get a magnifying glass and get a better look. I had no idea the amount of peening until I took a closeup macro photo of the case mouths.
Last week my old Vibratory tumbler died and I bought a Lyman 1200, some Lizard litter walnut media and some Nu-Finish car polish and this tumbler works great.
Bottom line, the vibratory tumblers will not make your cases sparkling clean, "BUT" you can fall asleep and let them run all night and not peen your case mouths.
I now switch between vibratory tumbling and wet tumbling and have no complaints. I also remember my sore fingers rubbing the cases with 000 steel wool before I had any type tumbler.
The best thing about wet tumbling is if you have firearms that throw perfectly good brass away and makes you go look for it. The wet tumbling and SS media will scrub the cases clean of any embedded dirt and grit that can scratch your dies and cases.
I got a new shiny toy two weeks ago and when you shoot it it gets dirty, you clean it and then start the dirty-clean cycle all over again.