Gravity is very pretty, and actually pretty well done scientifically, which i believe they've made a big point of in some of the advertising.
However there were 2.5 major "errors" that i noticed, both of which are covered by the Bad Astronomy review.
One of the problems is rather spoilery, so i won't go into it. The other 1.5 is basically that orbital mechanics say that the objects they needed to travel between in the movie wouldn't be that close together, and even if they were, you couldn't get there the way they did. At least as it was portrayed by the movie they simply pointed at where they wanted to go and fired off some thrusters. As any veteran of Kerbal Space Program, or hard SF lit in general, knows you can't get to a different specific point in orbit without doing some complicated maneuvers. If you squint really hard and pretend that they actually had much stronger thrusters than were actually available and that they did the proper orbital matching without going into details about the exact maneuvers required in a way that the audience could hear, it could sorta work. Sorta.
But as i said at the start, except for those two points it was an excellent movie.
Sleepy Hollow on the other hand doesn't really pretend to make any sense, and that's okay. There's magic and witches and demons and the apocalypse and secret histories and conspiracies by the founding fathers and Rip van Winkle style "time travel" all mixed up.
The female protagonist is cute and kicks at least a moderate amount of ass. Under other circumstances i might say she kicks lots of ass, but she's somewhat overshadowed by past Ichabod Crane, who instead of a meek school teacher was apparently a kind of 18th century James Bond under the direct command of General Washington. On the other hand, 21st century Ichabod Crane is also kind of overshadowed by past Ichabod Crane. He's obviously supposed to be a fish out of water at this point, what with the waking up a couple centuries later and not knowing what's going on with anything. Presumably as the series progresses the Lieutenant will step up her game and Ichabod will get his shit together and they'll both end up kicking ass.
It is a horror series, but it's not _that_ scary. At least not so far. There's only been a couple "jump out and go boo" type things so far, and hopefully that will remain to be the case as things progress.