I have an 03 CR250, my neighbor has a 05 YZ250.
My CR has a Pro Circuit pipe and spark arrestor, and I installed a Keihen PWK carb.
His YZ has a big tank, and a spark arrestor.
Yes, the YZ has more low-end, it's snappier. The CR has a bigger mid-range hit and out pulls the YZ when revving the snot out of it. I don't do much tight woods riding, but with a little clutch work, my CR gets the job done. A flywheel weight would probably help, and if it becomes a real issue, I could always have the CR ported and have the cases filled for more low-end power. The CR's motor doesn't suck, it's just not as good as the YZ unless you're in the dunes or going WFO.
That said, if I was starting from ground zero as you are, I'd wait for a YZ. If you want wide ratio gears, it's easy for the YZ, not the CR. Working on the YZ is easier, as the CR's perimeter frame always seems to be in the way.
Lastly, your local KTM dealer might not be too good, but the internet makes that a lot less important than it was years ago.