I learned and cleared T13 through PF in the last two weeks before 2.55!
I learned a lot of things, but I think mainly I learned a lot more about PF culture than the actual fight itself, haha. I, uh, learned that advertising a phase 3 practice party will inevitably result in a party that gets stuck in phase 2; advertising for a clear party with phase 4 exp will result in a party that gets stuck in phase 3... I like to give people the benefit of the doubt, but it's really mortifying to see people dying all over to divebombs every single time. (;T vT)
And uh, yeah, people... I never really liked the idea of blacklisting people because they perform poorly, but after a while of PFing I started getting a lot of people joining my PFs just because they saw my name on it ("hey, I know your pf says p3, and I haven't gotten that far yet but it's ok, right?", "your pf is in Japanese and I don't know Japanese at all, but it's ok, right?"). It got to the point where I started getting afraid of pfing for a clear party because I knew that 300 dps mnk was gonna join (or the pld who thought foresight and only foresight would save him from Flatten, or the whm who wasn't healing in phase 1 because he wanted to "conserve mana", or the tank with phase 4 experience standing outside the neurolink during teraflare in one run, and "forgetting" to LB in another run and having to ask the other tank what the timing for LB is).
So, yeah, I guess I learned to stop being so nice to people and just blacklist anyone who really messed up a lot. (I ended up removing them from my blacklist after I cleared, though. A lot of them were nice people! Just. bad. or liars, which i suppose makes them less nice)
Not to be totally negative, though, I did end up making friends with some people! And we did manage to clear it in the end, so. :D it is totally possible to PF for a T13 clear if you're willing to put up with a lot of silliness.
I've also PFed T10-12 and cleared them weekly that way. Usually they go pretty ok, although I've learned that PFing on reset can be a total crapshoot. Sometimes it goes perfectly smoothly, other times you get people pretty obviously trying to get ninja carried. Ironically I got my smoothest runs on the nights before reset; I guess a lot of people are just really busy during the week.
I also PFed an Aim to clear T9 the other day with a friend and... well, uh, I was under the assumption that "aim to clear" means people are generally confident enough in their skill and knowledge to go for a clear? At least know how the mechanics work, right? But I ended up getting people who pretty obviously had no idea how phase 3 and 4 worked and because of that there was no way that party was going to clear at all. Maybe I'm just naive, but I really wish people would be more conscientious when joining clear/aim to clear parties and to stop treating them like practice parties. :(