Well, it wasn't great, but then it wasn't completely bad either. I liked the use of Genesis/biblical sort of symbolism, with the creation of the planet in seven days and the fact that Jenny was created from the Doctor (echoes Adam and Eve somewhat). It wasn't heavyhanded, though the plot still seemed kind of flimsy and the supporting characters suffered a little from little development. Martha's storyline was kind of pathetic and didn't seem to do much to advance the plot. Killing off her Hath companion didn't seem necessary either.
Also: Donna telling Martha she plans on travelling with the Doctor forever is just the worst foreshadowing. I don't know the specifics for the finale, but it's so obvious that Ten and Donna's idyll is going to be shattered. Like shattered in a 'Doomsday-we-can't-be-together-anymore' kind of way. Heck, even Martha seemed to know that it was going to go all pear-shaped eventually.
Maybe it was just me, but this episode seemed full of plot holes, particularly with the Time Lord biology and the Hath. Travelling in the TARDIS means that the Doctor and his companions have some sort built-in Babelfish to translate alien speak. Yet Martha can't understand the Hath? It's an interesting angle, to have her talking to them without quite knowing what they're saying, but odd given what's already been established on this. They didn't even try to explain it either.
Yeah, I still think it was still gimmicky casting, but Georgia Moffett perhaps gets away with playing Jenny because I see a slight physical resemblance between her and Tennant. Slight enough to imply a familial connection. The blonde hair could totally be Romana II's though. Just sayin'. I thought her bubbly nature would annoy me when I saw it in the trailer, but it didn't particularly. It probably helps that the character still has a lot of growing up left to do by the end of the episode.
I'm glad they didn't seem to completely ignore Old Skool canon. Sure, Susan didn't get mentioned, but at least the Doctor mentioned he had children. I always pictured him as having one child, but he said 'them', so there's more than one. And one of those children would've been Susan's mother/father, so! Part of me sort of wonders whether the Doctor was angsting because Jenny looked like one of his dead kids. That said, as curious as I am about the Doctor's wife/children, etc, it's one of those things that the showrunner/writers can't address, rather like the Doctor's real name. The character has to retain some mystery. I suppose the idea of creating Jenny in the New Skool canon is so that mystery can be retained while at the same time viewers get the chance to see the Doctor as a father figure, as opposed to the mentor/authority figure/teacher/possible romantic interest/etc that he's been depicted as to date.
Stephen Moffatt recently said at Comic Con that bringing Jenny back at the end was his suggestion, though I was amused to hear thatin retrospect he wished RTD hadn't taken the advice. I wouldn't mind if the character came back (but please, no spin-off!), though I'd be more interested to see her in action with Tennant's successor than with Ten again. Also? She so should've taken the pimply-faced soldier she kissed with her as a companion. Just for the potential LOLZ.