PokerTracker was never a No Limit tool - I only really use it to monitor my own progress. In NL you tend to asses ppl in different ways. The big one is size of bets and betting patterns.. PT doesn't help here. As soon as you see someones cards you have a pretty good idea of what they're playing. PT is also pretty useless against ppl who mix it -in fact it can be downright misleading...
Occasionally I kick up GT+ with PT, but I prefer not toplay with it on-uses my notes. I know that ppluse it a lot at the limits I play at now ... but I don't feel at a disadvntage when I havn't got it on.
I do like it for historical anaysis...
Limit... well I can't comment. With poker you always play the house rules, if the house rules say you can use up your time bank in a tourney

or whatever.. then thats the game.
Poker was originally called the cheaters game... Is it really any worse using PT than using chat to tilt someone ?