As far as I can see, it's obvious that Apple has dropped support for Handoff with 2011 MBP's, at least with the beta so far. I would imagine this will remain the same, as Handoff never really "officially" worked for my MBP (early 2011) even with the first beta, regardless of the option which showed in the "General" pref pane at the time.
It's kind of irritating for those of you who do not do some research before asking questions... but in order for Handoff to work for a machine that it does not natively work for, you need to upgrade your wireless card to the 2012 . If your system does not support the new wireless card (in other words, doesn't have all or the right cables attached to the motherboard), Handoff will not work for you, regardless of what you do. Simply adding a bluetooth dongle will not work either, unfortunately...
So, for those who have early 2011 MBP's and who are willing to upgrade the wireless card, you may have luck with keeping this enabled, so long as you follow the instructions that the user @iammatthius included on page 4 on this thread:
1) open Terminal type sudo nvram boot-args="kext-dev-mode=1"
2) reboot your MBP
3) your wifi will not be working at this moment, replace the file IO80211Family.kext in Go>Computer>System>Library>Extensions
4) open Terminal type as below:-
sudo chown -R root:wheel /System/Library/Extensions/IO80211Family.kext
sudo chmod -R 644 /System/Library/Extensions/IO80211Family.kext
sudo kextcache -system-prelinked-kernel
sudo kextcache -system-caches
5) now reboot your MBP again.
6) now you will see System Preferences>General> will have handoff enable option
7) open Terminal type kextstat | grep AirPort
As with any OS modification like this, it is only temporary. Each time there is a system update (and the IO80211Family.kext is modified, removed or updated), Handoff will not work for you anymore, and you must go through this process again each time there is an update which changes this. Some updates may not affect our little modification, so unless you do not see the option anymore in the "General" pref pane, you shouldn't worry about redoing it.
However, a word of advice, I would keep a copy of that kext file, as you never know when that link may break. I would also encourage whoever is able to modify it to work with our setup to keep it up-to-date.... A small request from me and the community