My view of Sora wo Kakeru Shoujo
Author recently asked about opinions on Sora wo Kakeru Shoujo (hereafter 'Sora Kake'), with special concerns over Moogy's comments calling it the successor to My-Hime since he had had a bad reaction to My-Hime's thematic changes (to summarize Author's entry very briefly and not very well). So let me take a shot at it, from the perspective of someone who's so far watched nine episodes.
I would summarize Sora Kake as entertaining but fluffy, something that is not attempting to tell a deep and complex story. It clearly takes itself far less seriously than My-Hime ever did, which may be either good or bad depending on your views of that (if shows that deliberately set up somewhat over the top and innuendo-laden situations and then play them straight are not your thing, then you may want to give Sora Kake a pass). A commentator at Moogy's called it playful, and I think that is a good description; Sora Kake is clearly having fun.
(I think you can view Sora Kake as partly a low-key parody of its general genre, although this may be going somewhat further than the creators intended (and don't ask me exactly what Sora Kake's genre is).)
On Author's specific concern: since this is anime I'm sure that there's going to be serious elements every so often, and we've seen some hints of them so far (including in the opening). That said, Sora Kake going all serious would be far more abrupt and lurching a change than it was in My-Hime (which started dropping real hints quite early on), and it would completely surprise me. And yes, Sora Kake has shown us conspiracies and evil and mysteries and so on, but so far they don't feel particularly surprising to me; if it makes sense, they all belong in the sort of story and genre that Sora Kake is.
Is this a recommendation? Maybe. I'm a pretty undiscriminating consumer of anime, so I'm easily entertained. And there are elements of Sora Kake's presentation that may really irritate people (I have read of bad reactions to one character, for example). In thinking about it, I feel that the opening is actually a pretty good representation of Sora Kake's mood; if it gives you hives, you will probably not like the show. Also, the first episode is pretty typical of the feel of later episodes, so if you don't like it I suspect that later episodes aren't going to be any better.
(My views of Moogy's comparison itself are complex enough that they don't fit within the margins of this entry.)