Stills or video for time lapse on 7D?

Any preferences or differences?

Should I use stills or video for a time lapse on a 7D?

Stills are higher quality because you can shoot in RAW at a super high res, adjust the exposure with LRtimelapse and export as a high quality video. Stills allow slow shutter blur, video doesnt.

LRtimelapse? What's that?

I've never been able to make effective time lapses, to be honest. My white balance and exposures tend to be all over the place--I get jumps in exposure, or everything goes dark (if I'm doing a time lapse of a sunset for example). I shoot at manual, and I've been using Magic Lantern on my T1i for a while. I just can't quite get my time lapses to be where I want them to be, you know?

Exactly, thats why you need LRtimelapse because it lets you adjust every single setting AND animate them over time. So if a sunset for example gets too dark at the end, you can animate the exposure slider UP on the last frame so when the video is exported, it looks like the exposure was constant from start to finish. LRtimelapse removes jumps, flickers, white balance issues, all that. You need to look into it and pay for it (or get it "from a friend"), worth the money. I've made a music video for fun once and it had a few LRtimelapses I made of clouds, and people liked the timelapses so much that it got me a lot of business, and no one cared about the rest of the video. Funny stuff.

http://lrtimelapse.com​/

Study their tutorials heavily, they got tutorials on youtube and vimeo for any kind of timelapse you want. Alternative option: find a different, yet free program for timelapse help that does what you want.

Wow, just discovered LRTimelapse and this is some freaking incredible software.