The XH series was Canon's answer to the Sony 3CCD Z/FX1. The high resolution sensor with very flexible image configurations was very popular due to the lower price and excellent resolution. The new XH series doesn't change much, but is rather a refinement with minor changes like more robust FW ports and more custom functionality. The best addition is the new EVF secondary output, giving those who use external monitors full peaking, zebra and other important data that was available to all camcorders before. The ability to switch gain at 0.5db also allows very precise control over the image. There isn't 24/25/30P but Canon still maintains F mode, which actually slight drops resolution but gives a progressive look. The XH series also supports Focus Enhancements FS-CV hard drive fully, beating Sony's own HVR-DR60 with a 3rd party product. Hopefully it will fit the housings without too much modification.
It seems that in the US, it has maintained its price tag but in Europe, it is markedly more expensive than the original XH.