I love PPCs. The Awesome C is my favorite mech, I think. It does amazing damage when everything is working smoothly.
It's a huge pain when you play on a server where you've got any sort of desync or server-side lag though. Having your shots vanish server-side when they're dead on (especially with the leading required and the cooldown you've got to suffer through a miss) really sucks, especially compared to the better hit detection for direct fire or lock-on weapons.
It happens on a variety of servers with a variety of pings. I've had it happen in 1v1 servers and on massive games, and on various maps, so I don't know that it's a server-overloaded issue (like, for example, Clearcut with max players). I've even had it happen separate from warping, so I'm not really sure what the underlying issue is; if I was, I'd submit a bug report, but otherwise I'm not too sure my complaining will be helpful without an analysis of a common theme to work off of.
Suffice to say that I have no problems with the PPC balance-wise, but something in the code may need to be tweaked to give it more reliable performance!