Even Aniston does not know what she was thinking when she did this movie but I rather liked her role as Emily, the girlfriend/manager of Chris, a wannabe of Bobby Beers, lead singer of the metal band Steel Dragon.
Emily is not a groupie, she is a self-professed businesswoman, who sees talent and determination in Chris and wants his tribute band to be a success. I liked seeing that she took out loans and did small business ventures -- she had a life other than "helping her man", and, when Chris' career soars as a replacement to his esteemed Bobby Beers playing with his idols, this becomes a conflict between them.
As for Chris -- who morphs into "Izzy" when he is famous --- he doesn't know where Steel Dragon ends and he begins. He hasn't in ages, as his friends and family points out. Will he ever?
I did like that Chris' parents are so cool, they support his rock n' roll fantasies and come to his shows. It would be too cliche to have a dad who just doesn't understand him.
Mark Wahlberg demonstrates the same vulnerability he brought to Dirk Diggler in "Boogie Nights". He is believable as the kid who just wants to make his dreams come true. I like that they play his song "Good Vibrations" as he started his career as a rapper before becoming an actor. It was a fun and fitting tribute.