Meh. I was not impressed. I don't like Eliza Dushku so that didn't help but objectively I don't think she can handle the acting this show will require. I didn't believe her as a negotiator for one second. It's like Eliza didn't have a clue how extremely powerful women act outside of Hollywood. And what kind of father would trust his daughter to a fake? Give me a break.
The way I see it, this is not that different from Alias in the pretending to be lots of different things part and she has about as much believability as Sidney did.
But the point of it is that Echo wasn't pretending. They imprinted her with this personality, she actually becomes the person, she doesn't pretend at all.
Also, as someone said, the thread of the story is Echo's burgeoning self awareness. She doesn't necessarily start to remember, so much as realise that she is someone, so far as I've read.
Overall, it's Joss Whedon [And Tim Minear, Steven S. DeKnight, and other such talented Whedonverse writers], so I trust that the whole Active memory wipe won't get stale, and that it will go to very interesting places if Joss is allowed his vision.
I also disagree completely on Topher being Xander-lite. The only comparison really is geekyness. If he's like anyone from Buffy, to me it's Warren. But again, not enough to have any bearing on the show, imo.