I have two and they get along GREAT!! In fact Tilly, our first, has gotten better as far as her separation anxiety. I guess she was just lonely. JJ and Tilly are opposites though. JJ likes to play and Tilly likes to sleep all the time. So when we go shopping we know to buy JJ toys and Tilly clothes.
I was worried getting two but it was the best decision. They are best friends.