Pgrens are probably the most underused unit in the game. I can't think of one that is used less. 
I go double Sturms some games more than I've ever thought about making a Pgren. They always end in disappointment, a costly squad that is fiinicky to use, and if you upgrade to shrecks they'll just get crushed and focused so hard it makes you regret that decision.
Man, team games really are a different beast. 
In nearly every 4v4 game (not an exaggeration, at least 80%) if there is a Wehrmacht player, pgrens will see use, and about half of those games 2 will be used. 
I get that things are different in 1v1 but pgrens are very common in team games.
edit: Ok so this is just anecdotal but I just went to twitch and I see Price doing a triple-shrek squad that can one-volley t-34s. It's just hilarious. 
Though in team games, this isn't actually uncommon so eh.