Yes, this episode was awesome. Even though they are slightly deviating from the books, it's still awesomesauce on a awesomesammich.
Eric gets..well you saw a taste of what he's really like. Most vampires are like that with their maker. Sure Jessica isn't quite like that with Bill but she's a young vamp, it takes time for the bond to form.
As for Mary Ann, its no spoiler she's a Maenad. Basically, even vamps are scared of her. I won't say what happens but you may be disappointed unless they rewrite it for tv.