While they're an excellent trio of camcorders, the Vixia HF S21, HF S20, and HF S200 are significantly more expensive than their respective competitors are, especially given the S20 and S200's lack electronic viewfinders. If you can forgo some of the subtleties of its manual controls, you can probably get what you need with cheaper models.
The largest and heaviest model in its class, it's nevertheless comfortable to hold and use, and will still fit into a roomy jacket pocket.
Canon's manual control dial functions the same as Sony's does. You press and hold the center button to select the dial's function: manual focus, exposure compensation, aperture or shutter, mic level, and automatic gain control limit--capping the signal boosting in low light to minimize visual noise. All the options are available via the touch screen as well.
Canon packs a lot of stuff in the LCD recess, including buttons for switching between shooting and playback, video snapshot (four-second clips used to create a "highlights reel" effect) and a pair of SD card slots. While it's nice to have a pair of slots, I suspect this is partly Canon's way of compensating for the camcorders' lack of SDXC support; you'd need two 32GB SDHC cards to get 64GB, the minimum size SDXC card.
The component, composite/headphone and wired remote jacks sit underneath a slide-down cover. I think the headphone jack location is awkward for shooters who use the headphones and EVF while recording.
The top of the camcorder looks a lot busier than it really is; it basically consists of the typical power, photo and zoom switches, plus a bunch of lights and labels. Further forward are the accessory shoe and a pop-up flash/video light combo. The stereo mics rest on either side of the large lens barrel, with a mic input just below the front strap connector.
The zoom feels very nice, and it's pretty easy to maintain a steady rate with it.
Those parenthetical additions surrounding the "8.0 megapixels" logo are actually raised rubberized bumpers that give you a little extra grip--a very nice design touch.
On the grip side of the camcorder is a small auto/manual switch (located where you see the green spot) and a flip-up cover under which the Mini-HDMI and USB connectors reside.
The HF S21 has an EVF; the the HF S20 and S200 do not.
Canon uses the limited bezel space for one dual-function button. While playing back video, it handles the wireless uploading; while shooting video, it lets you toggle between the Powered IS and the current image stabilization state. In playback, it allows you to downconvert HD video to standard definition in-camcorder and copy to an Eye-Fi SD card for wireless upload.
The low-resolution EVF is better than nothing--which is what the HF S20 and HF S200 offer--but pretty coarse for manual focus. However, between the focus-assist magnification and peaking for edge detection, it's relatively usable. Because of its location, the diopter is a bit annoying to set without poking your eye out; your eye and your finger need to be in the same place.
The battery recess is clearly designed to hold a larger battery. I suggest you budget $75-$100 for the higher-capacity BP-819 because the supplied 890mAh model is woefully underpowered.
Thanks to a large, high-resolution LCD and--mostly--big virtual buttons, the bulk of the interface is one of the most streamlined and easy to use that I've seen on a touch-screen camcorder. (Peaking and Zebra are turned on, hence the odd red pixels and crosshatching on the background image.)
The only place where the interface falls short is in the menu system, and there it's teeth-gnashingly frustrating to use. For one, the scroll area is on the inside edge, so your hand blocks the display while you're scrolling. Second, the multitouch-like scroll operations make it impossible to accurately move a single entry at a time, so I always scroll past the entry I want and repeatedly select the wrong entries along the way. At best, it will take some getting used to; at worst, it will make you nuts.
(Peaking and Zebra are turned on, hence the odd red pixels and crosshatching on the background image.)
Like Sony, Canon defaults the video quality to the second-worst option, 7 megabits per second at not-full-HD 1,440x1,080-pixel resolution. That means the video you get out of the box looks more like the bottom, artifact-ridden grab than the top. This might make sense if it was a cheap model with videos destined for nothing more than quick-and-dirty Web upload, but not in a $1,000+ model. There's no reason not to default to the second-best, 17Mbps full HD mode, which looks quite good and likely won't have the playback issues you might run into with the best-quality 24Mbps model.
(Unfortunately, I was unable to get sufficiently comparable grabs for each mode. Nevertheless, I thought they were close enough and worth the illustration.)