Actually the comparison of AVCHD to XDCAM-EX is a great example of the efficiency of AVCHD. I've done comparisons with the S10, HF11 and EX3 clips. The quality at FXP 60i mode is close the XDCAM EX at 35mbps in terms of compression artifacts. I'd bet only pros/broadcasters could easily see the quality difference on cursory viewing on a big 50"+ HDTV. The most obvious flaw is interlaced chroma, since the signal is interlaced. But my opinion is nothing compared to Adam Wilt, who tested the HF11 and found much more detailed results in vigorous testing.
It's not an equal product obviously, but the quality is reasonably close enough, especially in good light. It's definitely very comparable or better than 3xSensor HDV cameras. The Canon AVCHD at 24mbps is so good it was evaluated by the BBC (not for main format but as a B/C/Mini supplemental cam).
In muddled design, the Canon picture is a little less contrasty and saturated than the Sony picture in general. Sony's slant toward saturated, high contrast images appeals to the consumer market, while Canon's slightly flatter image actually appeals to prosumer+ as it allows for easier post-correction (not that 8bit recording 4:2:0 is very correctable in the broadcast world). This is where it's confusing since it's a consumer camera, but obviously an enthusiast consumer's variant.
Steve, XDCAM-EX is long GOP 4:2:0 MPEG2 interframe, not intraframe. AVCHD transcoding is required because of the compression demand on the CPU. Right now, most computers would struggle to get 18fps on NLE since NLEs convert to their underlying codec (EG: PRORES for Apple, DNXHD for Avid or uncompressed) for any effects etc. Thus I think AVCHD requires a slight different workflow. Copying into the computer, the files should be viewed not by NLE but a program like VLC to mark the "keeper" clips. Then after that, one converts the marked clips into the NLE. This workflow is for consumers, especially those who don't have high powered computers to transcode AVCHD easily.