First of all you wrote a very nice plugin! This one is going to be huge!
I see that is still in BETA testing so I just want to help you out.I found one problem with your module that is CRITICAL.
Use case :
1) You have 2 users.
2) Vote 'Like' with first user -> counter for post gets set to 1
3) Vote 'Like' with second user -> counter for post gets set to 2
4) Vote 'Unlike' with second user -> counter gets set to 0 instead of 1! However I have enabled 'Show voters after post/page content?' and I can see the first user. But the counter is 0.
I will write also a list of futures that I think is very important to be added for the success of this plugin in another topic.