I just bought the RCBS primer pocket brush combo (#9574) and used it on a lot of brass I was prepping. It definitely gets the primer pocket clean with a few twists, but I am noticing that it is leaving deep marks in the primer pockets. This shouldn't surprise since these are stainless steel wire brushes being scraped against brass.

My concern is:
1. Marring the primer pockets is just going to make the primer fouling harder to remove next time.
2. Scraping brass is going to reduce uniformity of my primer pockets -- maybe even significantly deepen them -- over time.

Should I be angry and return this tool? Or am I being unduly sensitive?

Hmmm. I guess I would point out that just priming pockets with time-hardened carbon in them creates scratch marks on the sides, but not enough to affect re-use. My primer pocket depth uniformer also leaves visible marks on the bottom, but I haven't had issues from that. I rather doubt the brushes can take off a significant thickness of brass during a case's normal life? Load and fire and anneal, etcetera, two cases over and over, cleaning one with those brushes, until you get to the end of their lives and see if a depth micrometer shows a significant difference in primer seating between the two or over the original measurements in the one you were brushing?

You might try a variant of Humpy's case mouth treatment? Use a Q-tip to wet the inside of the primer pocket with Ed's Red and let it sit awhile before brushing. That may soften the carbon enough that you don't need to brush very hard? You will, however, want to rinse that stuff off with mineral spirits and let them dry before loading them.

I'll go back to my Lee primer pocket cleaner before I move to solvents. In theory I suppose that tool is also hard enough to remove brass, but maybe because it's a single flat blade that tends to stay perpendicular to the pocket, as opposed to a bundle of wires like the RCBS that can twist and independently gouge, it didn't seem like it was doing any noticeable damage to the brass. But it does take a little more work with the Lee than the RCBS to scrape everything out.

I'll see if I can get some good pictures later of the differences....

I have noticed this too, not impressed with the RCBS cleaner at all. I would think that over a period of time it is going to take out more brass than I would prefer!

Here's a pictorial comparison: http://emptormaven.com/wp-content/uploads/2009/07/LargePrimerPockets.jpg

Dirty pockets on the left, three cleaned with the RCBS tool on top, three cleaned with the Lee scraper on the bottom. It looks like as soon as you've used the RCBS brush once you'll need to stick with it since the pocket floors are no longer flat enough for a tool like Lee's to make full contact!

Based on this I'd avoid the RCBS brush, though I may have to hold onto it to successfully clean the brass lot I just used it on in the future....

I'm a bit puzzled as to why anyone would pay for a primer pocket cleaning brush, when you can make one in 5 minutes.
Pick up a 223 case at the range. Pretty much any brass, bottlenecked rifle case will work. Squeeze the neck and shoulder flat, using a vise or a pair of pliers. File the sides of the flattened neck until it just fits into a primer pocket (whichever size you want). Done.
To use, stick the files down neck into the primer pocket you want to clean, and twirl, just like you do with the tools you buy.
The home made versions won't scratch up the primer pocket, but do clean out carbon.

Good idea. That has the advantage of not putting a harder metal in contact with the pocket during cleaning. Though at under $2 it's not like the Lee tool cost is a factor.