I have a curve and love it, brother just got a bold. From using it the main difference is the speed, it is lightning quick, and definitely looks sleeker than the curve.
Other than that the differences aren't too overwhelming, the Curve is still a great phone and a good deal right now.
I won't front, I don't own a blackberry (FWIW, I have played with one.).
But the STORM looks absolutely amazing. Textile feedback from a touch screen?! It's a technological breakthrough.
I heard the qauntitys of these are pretty limited right now though. People were lining up to buy this at many stores on relase. A lot of folks towards the back of the line went home dissapointed.
I watched Rick A. use his iphone at the last RX bash for a little bit and I have to admit, I was just amazed by how fast and seemlessly he could do everything.
It's definatly a nice gadget, going to be hard to top.
Only bad thing I heard is that G3 network eats the battery quick.