Well they seem to be alright for the most part now, but early C93's were some of the worst rifles Century made, improperly pinned barrels were the biggest problem causing headspace/bolt gap to shrink rapidly, they would also grind the bolt heads rather than change the rollers to adjust headspace/bolt gap, and crooked cocking tube and front sight frames were somewhat common.
Like I said, lately they seem to have gotten things under control and your chances of getting a good one are much higher now, but it would be best of course if you could look at the rifle in person to check it out for those issues.
I bought one a few years ago, bolt gap held fine, but the front sight was so crooked I couldn't adjust the sights enough to get it on target, I sent it to Parabellum Combat Systems and had the sights straitened and a paddle mag release installed, now its the rifle I use in the local HP matches.