I've used mine for 5 years with 3 different Surefire lights, and my spring just broke 3 days ago, so I wouldn't call that an issue. I work midnights in a prison, and I unhoster and reholster many times a night every night I work.
The finish wear issue only occurred with my first light which was an older generation. It wore the crap out of the finish too, but it definitely wouldn't let my light fall out. The only way it came out was if I pulled it out. Switched to a 6PX pro, and the finish wear problem wasn't an issue anymore. I think the V70 was made for this generation of light (just guessing).
Bought a Peacekeeper the other day, and got a new V70 holster. The peacekeeper barrel shape is a throwback to the older generation. As a result, I'm already seeing a little finish wear on the tailcap. But I'll trade that for the retention the V70 gives. In that holster, I won't be losing my light, no matter what angle I'm sitting at, or even when I put my belt in my backpack when I go home. On top of that, it doesn't have a flap over the light that I've always hated on other types of light holsters.
Sorry to be so gabby.