I bought my R9 in Feb/07 and at first was happy, but then I had problems with FTE and replaced the recoil spring. I continued to have problems, the people here told me it was my ammo... so I changed ammo. The problem continued. I called the company (no, not THE company!!! but Rohrbaugh) and arranged for ship/return.
In three days my pup was home, new extractor/spring and has shot like a champ ever since.
So, despite the initial problem I would have to say that my comfort zone fell in around the 200 round mark. I need to speed-feed at least three or four mags, back to back, with ZERO problems before I feel comfortable carrying a gun for self defense.
Sure, the R9 had a problem, it was resolved, and right now I would trust my life to the performance of the gun.
ETA - I am thinking about some skateboard tape for the front strap. Any suggestions on brand or