Apart from the HSDPA-support, there are only a few other differences between the Curve 3G 9300 and the elderly Curve 8520. The newly introduced smartphone is said to be BlackBeryy 6 ready (the update from ver. 5 to ver. 6 should become available in the coming months).
On top of that it will also feature a built-in GPS receiver and there will be support for Wi-Fi 802.11b/g/n, too (the BlackBerry Curve 8520 had no GPS receiver and came with 802.11b/g Wi-Fi).
The rest remains untouched. We find the same 256K-color QVGA display as well as an optical trackpad and a comfy QWERTY-keyboard underneath it. Like its predecessor, the BlackBerry Curve 3G 9300 also packs a standard 3.5mm audio jack, dedicated music keys and a microSDHC card slot. And backstage there is the familiar 2MP fixed-focus snapper.