The biggest change is if you didn't adopt the ribbon bar in NX9, you're forced to now. Personally, I liked the change. but I think people were hoping Seimens was kidding when they said the classic toolbars were being retired.
Customing your NX desktop has never been easier.
If you used the "trim and extend command" to extend sheets, they split it off in NX10 to give "extend sheet" its own, more powerful tool
@ JHG1981
So much new new functionality; too much to list.
If you have a question regarding a specific functionality you want, we can try to answer it but first you really should read the What's New docs for 10 and 11.