Pretty average and by the numbers, really. The obvious solution right of the bat is to get everyone into the TARDIS and away from there, but of course access to the TARDIS has been cut off, forcing everyone to deal with the situation at hand. The Gangers are basically the same cliche done in every clone story. They have the memories of their originals, and therefore they consider themselves equal, but of course the originals don't want to grant the clones (Gangers) the rights they feel they deserve. The Doctor is naturally sympathetic and wants to help the Gangers out, but complications arise, such as humans wanting to kill the Gangers. A companion (Rory) gets involved and has a personal stake in things.
Really, this could be any generic Doctor Who story, or any generic clone story. There's not much new or original here, and so it's not entertaining or particularly compelling. I don't know, maybe I am being a bit too harsh, but it was boring.
And just how many more times do we need to see the Doctor standing at the TARDIS performing a pregnancy scan on Amy? We get it, she may or may not be pregnant. Surely the Doctor must realize that constantly staring at the monitor as it switches back and forth between positive and negative isn't accomplishing anything. And just how long do we have to wait until Eyepatch Lady is explained? Midseason or proper season finale?
And finally, could they spend at least one episode this season where they're somewhere other than an American desert that isn't so damn dark? Jeez, can't they afford light bulbs this season?