The best replacement for pia is ppa.

The best alternatives to pia are rated as following:
★★★★★  ppa
★★★★★  nda
★★★★★  air india
★★★★  btguard
★★★  hma
★★★  airblue
★★  mullvad
★★  airvpn
★★  purevpn
★★  hbl
★  torguard
★  astrill
★  air blue

Your alternative for pia is not listed? Suggest!
Speaking about pia, one probably shouldn't forget about vuze.

Other search terms related to pia and their ratings are:

★★★★★ vuze
★★ turkish airlines
You have in mind a companion for pia and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of pia in all years. Click on graph for more.