IQ is pretty similiar. There's a bit less noise but not significant. Nailing the exposure is key regardless of the camera. You'll notice better, more consistent AF, especially in AI Servo. Tracking will be easier. Not a 1 series easier, but definitely an improvement. One shot will be more precise. Again, not drastic but noticable. You can also keep your noise down a bit better with the 30D since you don't have to select full stop increments. If you're maxed out and need 1600 you can't do much about that, but if you only need ISO1000, you can use it. You don't have to automatically go all the way up to 1600 as with the XT.
Chris forgot already. He apologizes. 



