... it does appear that with (or maybe not even) an anti-aliasing filter and with ML you get high quality HD video with further control.
Yes, sortof!
With ML installed the 7D can shoot H.264 and raw video in two modes - regular and crop. Regular video uses the full area of the sensor but only samples some of the pixels (called line-skipping) - this is what introduces the nasty moire/aliasing. In crop mode, the camera only uses the center portion of the sensor and samples every pixel, so the skipping problem goes away (in theory it's as good as a still photo). You cannot shoot full-HD (1920x1080) RAW in non-crop mode, it's a limit of the way the sensor is read, so if you're after 1080p footage you either have to shoot in crop mode (which creates a very narrow field of view, similar to using the "5x" zoom button in Live View), or stick with H.264. Until very recently we had no fps control for crop mode raw recording, so the data rates being sent to the card were so high it was impossible to shoot full-resolution for more than a couple of seconds. Even now, you need the fastest possible cards (1000x or above) to record at the larger sizes. You're OK with a 64G card on the 7D, but a 533x speed rating will limit what you can shoot in raw video. These days the 'workhorse' card is Komputerbay's 64GB 1000x.
Your mention of 'further control' is a little different for raw video - yes, you do get to change your white balance and push the exposure much more in post-production, and as it's basically a series of still photos the quality is far higher, but the price you pay is
needing to do that post-production; which involves extracting the footage, color grading in Resolve or Speedgrade, then rendering out a new file. Unprocessed, the raw file is flat and often has messed-up black and white values, plus it'll be a long while before you can upload an MLV file to YouTube! If you've never done grading before, that's a big leap from "copy from card and press upload". Raw video is rightly something that we're all passionate about, but some days you're just hoofing a clip of your cat onto Facebook, and plain old H.264 recording is the way to go. ML doesn't stop you from doing that.
ML's very stable in photo mode these days - occasionally you can crash the firmware by pushing some of the obscure features too far (like focus stacking with motor speeds too high) but you just pull the battery and restart. If you have a
fast card the raw video recording is also pretty stable, nobody's blown up their 7D yet, but you're at the limit of what's possible so even things like attaching an HDMI field monitor can mess up the recordings, so you need to play with it and learn what works with your methods - don't install it the day before a commercial job! Personally I think raw video is good enough for B-cam work and personal projects, I don't know of anyone who'd rely on it to A-cam a one-off event like a wedding; but then the same was true in the early days of RED.
Adding a VAF filter from Mosaic will reduce the aliasing in regular mode
only - it has no benefit in crop mode, if anything it'll make the image a bit worse. It's also designed for dedicated video shooting, you remove it to take stills as the filter wedges the mirror up, making your viewfinder useless (it's possible to shoot stills via Live View, but that's a real pain and there will be a slight blurring of the image). The filter will work for both raw and H.264 footage, indeed with the huge increase in fidelity you get from raw files, having a filter is arguably much more important. I've been using one since they launched, but if you're doing mixed-media location work you need a second body for stills. Anything that ships with a set of tweezers isn't going to be installed in a field!
ML has made a huge difference to the 7D's video performance, and while it doesn't alter still image files the focus/exposure/automation tools are a massive help to folks shooting macro, timelapse, etc. The thing to remember is you don't
have to use it even if it's installed - ML doesn't remove any of the 7D's factory features, it simply adds more.
