I tried an update from the 5.5.x branch of Percona to the 5.6.x branch and it has gone horribly for me. After much strife I was able to get the 5.6.x branch to start properly, but then it wouldn't read my InnoDB tables (which is pretty much all of my tables).
I'm now trying to get 5.5.x running again so that I can do a mysqldump of the databases and just import them into the 5.6.x install, but I can't even get 5.5.x running anymore. It's giving me scary messages in the error log like this when I try to start it:
141210 0:42:54 InnoDB: Warning: table 'pc_xenforo/xf_news_feed' InnoDB: in InnoDB data dictionary has unknown flags 50. InnoDB: Dump of the tablespace extent descriptor: len 40; hex 000000000000000200000000022effffffff000000000004aaaaaaaaaaaaaafeabaaaaeaaaaaebae; asc . ; InnoDB: Serious error! InnoDB is trying to free page 799 InnoDB: though it is already marked as free in the tablespace! InnoDB: The tablespace free space info is corrupt. InnoDB: You may need to dump your InnoDB tables and recreate the whole InnoDB: database!