Hi Mike,
Congrats on your T3 purchase, it's a wonderful keyboard. I owned it for a few years before chosing to upgrade to a T4 last year (just after the T5 was unveiled & demonstrated).
I couldn't fault the T3 apart from only one thing perhaps was it look a fairly long time to load up the premium voices into memeory in comparison to the T4. My T4 has 1GB and I'm using nearly all it's capacity and it still takes about just under a minute to load in everything, I think the T3 took 5-7 minutes? Even so, that's only a very minor gripe and if you're not going to use the additional voices anyway then it won't even matter.
However, I know the T3 doesn't have the great vocal and choir voices of the T4 (which is arguably the biggest difference between the two) but before I upgraded to the T4 I was using the vocal and choir premium pack on the T3 which helped plug the gap between them, albeit a small one but it's still worth having if you use vocals and choirs.
Enjoy!
Take Care,
Danny