PT/HUD for tournaments not that useful.

From 2+2 below... My feelings exactly in regards to MTT play... but use TI to do the observation for you, esp if multi-tabling.

Re: How many successful MTT players use HUD's/PT in realtime
I used PT/PAHUD a lot. But I don't have the feeling that it helped me that much.

Usually in those large field MTTs you are rarely running into the same players twice. Also, once you have some stats on them, the table breaks.

The other thing I dislike about PT/PAHUD in tournaments is the dynamic of the table. People play differently when they have a bigstack/smallstack. If I have a nice stack and there are no super-shortstacks at my table, I raise like hell.
If half the table has 10xBB or less I even tighten up with a bigstack.

There is also M, Q, streak, tilt factor etc. you could be watching to make this a very useable amount of information from a poker calculator like Tournament Indicator.

What if you play the rebuy hour with a player and 2 weeks later you meet him at the final table only to label him as a maniac according to his stats?

When it comes to MTTs I've changed my opinion from PT/PAHUD to simply being observant and taking notes. I'm looking for players that call down light or can't be bluffed. I take notes about what players limp / min-raise from EP/UTG, if they are calling raises light. What kind of hands do they openshove from EP-MP for 20+ BBs or overshove the flop for 3+ times the pot.

When it comes to cash games there is nothing better than PT/PAHUD. Blinds stay the same, people play (almost always) the same, there is no bubble where people play completely different and so on...