All in all a brilliant update. I've seen that moving apps to SD card requires a class 6 (or 10?) memory card. Mine's a class 4 and it's working fine. Use Storage Sense to move your apps from the phone to the SD card. There's a multi-selector button at the bottom. Some won't move however but most seem to.
Cortana works great - UK user so had to set keyboard, location and speech to US English. Reigon format (like currency, date and time) work fine when set to English UK. Cortana is still there and being awesome.
Had to install the Facebook app to get the rest of my contacts back - go into People and you can install it straight from there and it will connect, restoring that previous functionality. While the People hub looks like it did in WP8, going into comments and photos just takes you straight into the FB app.. You might also find it useful to turn off message notifications in the FB app or you will just get duplicate notifications if you have Messenger installed too.