I believe its F11 now, Although you can force it to vb classic and still use F8.
From what I have seen debug mode doesn't carry over so when you press a button, even if you where in debup/step mode prior it wont' resume that way, IE you need to use breakpoints.
We are still in the process of switching over so i haven't had a whole lot of time with vb.net. Hope that helps though.