Had a few and they have varied quite a lot in Temperament. Current ones are really chilled but we've had a couple of loopy ones in the past - I think there are that many about they do vary a lot, like all breeds do!!
As the others have said it's a good mix as you get the speed and agility from the TB side, but they are very hardy and have good legs!!
In my experience they seem to be better if they are actually from Ireland.
Lovely mix, my daughter and I have shared one for 6 years. Responsive but safe hack for me and brilliant XC/showjumping for her. Just watch the feet, ours has flat feet and needs careful shoeing to keep him sound as his feet can bruise easily, apparently this is common and comes from the ID side.
a lovely mix: clever, generous, forgiving, finds a 5th leg. not always happy to go round in circles for hours though!
i had one by Smooth Stepper and one by Skyboy, both were superb eventers.