I, too, have both. In general, I think the new streamer is much faster than my original BD player. One thing I read is that bluetooth controllers are slower to wake than the RF controllers. Just something I'm still monitoring.
I have both the NSZ-GT1 and NSZ-GS7 as well and don't notice any differences in speed yet. I was waiting for the NSZ-GP9 and it was cancelled, the NSZ-GS7 dropped in price so I bought it. I do expect apps developed for the ARM processor specifically to make the newer model better eventually but as things stand now, the NSZ-GT1 with better code support is the better box for me. The Logitech K700 keyboard works great with the NSZ-GT1 but not as well with the NSZ-GS7 so I may have to learn to use that cool little Bluetooth remote, I have not used a little qwerty keyboard much and hate it so far.