I've been using PIA for a couple of weeks and I am mostly pleased with it, but a few things should be noted...
1. While PIA advertises port forwarding, you are only allowed on forwarded port, which is a problem if you like to run, say, eMule and a bittorrent client at the same time. Luckily eMule allows you to put the TCP and UDP listeners on the same port, but if you try to tell your torrent client to use the same port then eMule will be unable to get a high ID or use KAD.
2. Even if you can get away with a single forwarded port, port forwarding with PIA is very spotty. Only some of the endpoints support it, and no matter how I try, even many of the listed ones absolutely refuse to forward for me. I find myself always using one Canadian endpoint that has a higher success rate, but even then I often have to reconnect three or four times before PIA forwards a port for me. PIA support told me to turn off forwarding and connect to a different endpoint, then disconnect again, turn on forwarding, then reconnect to the desired endpoint. This does improve chances of getting a forwarded port, but it is cumbersome, to say the least. I have read other users reporting that the list of forwarding endpoints is not up to date, and that in fact some of the other endpoints support it, while some of the listed ones actually don't.
3. If, like me, you do your torrenting in a VM to protect your main files against malicious sites, you should know that PIA does not provide support for its service when used in a VM.
4. I am unable to use the highest encryption level for authentication with PIA, I am forced to use SHA1 for authentication and AES-128 for data encryption. PIS support told me that some older processors are unable to manage higher encryption levels, but I'm running a quad-core i7 Haswell. On hearing this PIA support fell back on the "Virtual machines are unsupport" argument.
5. Connectivity sometimes just goes away with no obvious notification. My P2P clients will suddenly drop to zero throughput and web browsers are then unable to resolve DNS or transfer any packets. The PIA icon in the taskbar will still be reporting a good connection, but the only solution is to disconnect and reconnect again.
YMMV