Hmm - to me it is distinguishable, but it isn't what I'd call easy - I have to concentrate a bit, eg. take a deeper look at it.
Not sure if this would be an option, but maybe you could display the mini-avatar next to the vote the user has given instead of using color as indication?
Not sure if this would be an option, but maybe you could display the mini-avatar next to the vote the user has given instead of using color as indication?