Shut down takes the same amount of time. I've read the camera cleans the sensor when shutting down though so that may not speed up. The menus are still pretty lagging when using the wheel control. Can't say I notice an improvement there.
I think the jpegs are improved maybe a few percent. I don't shoot RAW since it's nearly impossible to match the jpeg output unless you want to spend a lot of time tweaking each image. With 18Mb jpegs though, you have a lot of room to edit or crop.
I did lose the micro-adjust for the lens when I upgraded the firmware though so if you have any lens with special setting, better write them down. I have the Tamron set to +7 since it was front focusing according to tests I did with the chart on this website.
Nikon D70 Focus Chart