Though I really liked Canon's prosumer Vixia HF S series, I couldn't fully endorse the HF S10/S11 because it lacked an electronic viewfinder, a feature that higher-end users appreciate--it's easier to hold the camcorder stably while using one, and it tends to be easier to use than an LCD in bright sunlight. So I was quite happy to hear that Canon had opted to put one on its highest-end model for 2010.
This year's HF S series of AVCHD camcorders consists of three models which, as usual, differ by memory configuration; in an interesting move, they will all incorporate two SDHC/SDXC-compatible card slots. The aforementioned EVF-equipped HF S21 will have 64GB built-in memory and run a pricey $1,399. The HF S20 drops to 32GB and $1,099, and the slots-only HF S200 will hit $999.
The key specs remain the same as their predecessors: 10x lens with Canon's latest optical image stabilization technologies, including the new Powered IS capability for theoretically improved stabilization at the telephoto end, and 1/2.6-inch 8.6-megapixel CMOS sensor. Canon says it has tweaked the sensor for improved low-light performance and enhanced the Digic DV III processor for better rendering of blues and purples.
New, however, is the switch to a touch-screen interface on a big 3.5-inch 922K LCD. This enables features that I've always liked from Sony and Panasonic's touch-screen models, like spot focus and exposure, plus a Touch and Track mode, which tracks the selected subject while it's in frame. But I'm generally not a fan of touch-screen interfaces for capture on cameras and camcorders--they're fine for playback, but tend to be too clunky for quickly changing settings while shooting. The large size of the LCD can make a big difference for the better, though.
All the models can downconvert and save video to standard def MPEG-2 files, which you'll be able to wirelessly upload if you have the requisite Eye-Fi card. They'll also support relay recording, the automatic overflow of video from one medium to another if you run out of space, add native 24p capture, include LANC terminals, and provide a six-blade iris effect for improved appearance of out-of-focus elements in shallow depth-of-field shots (the iris is actually two-bladed).
Expect to see these models in early April.