I just watched it tonight and it was everything I expected, in a good way, really, it's awesome!
I've not read the comics so can't comment on the similarities but it seems to be the same humour and action that I gather is in them.
It's totally deserving of its decent review scores!
Morena doesn't seem to have aged since Firefly either, in fact quite the opposite and as for Mr Reynolds... Cracking performance!
I'll never look at a unicorn the same way again..