I actually quite enjoyed the first series. I was compelled to watch through to the final episode to see the characters story arc's develop.
Yes there are the typical Sci-fi clichés (maybe 4400 by the time the show is finished?). But I would say that this is a Sci-fi show and not a Sci-fact show, and by it's very nature it's a work of fiction, thus real world science doesn't really matter or nessecarily apply.
The scene the first post was alluding to was (I'm sure) not intended to be a dazzling display of the script writers grasp of near and outer orbital rocket science, but a characterization of both the governmental paranoia and hopeless desperation that humans can exhibit when faced with seemingly futile situations.
Personally, I don't think the acting is too bad, yes it does smack of countless other Sci-fi shows and draws heavily on many common themes running through all Sci-fi series, but what shows don't? There is little originality in Sci-fi these days, but the premise of this show is at least relatively unexplored.
How many shows do you know that effectively try to portray the multitude of challenges that face abductees when they try to re-integrate into a society that seemingly doesn't want them, can't understand them or are jealous of them?
Comparisons are inevitable, but when you're subconsciously thinking "Mulder and Scully" or "Rouge and Wolverine" while you are watching supposedly new characters then as a script writer you've got to try to distance yourself from what could easily be considered as stereotypes. This is probably my greatest (and only real) criticism.
If the script writers were just a little less derivative, and a bit more adventurous then I think we have a winner.
P.S. Oh, and they need to stop the re-caps at the start of every darn episode, the fast forward button on my Tivo's getting worn out as it is.
Mqark.