I've been happily using K2 Cinch bindings for a few years now, and just recently made the move to the '08 CTS.
I see many comments about weight, so I weighed mine and compared them to some traditional bindings that I own. 2008 Cinch CTS: 45 ounces each. 2005 Cinch 05X: 50 oz. 2007 Burton Cartel: 35 oz. 2002 Burton Mission Black: 35 oz. 2006 Salomon Malamute boot: 48 oz.
So 10 ounces difference is about a 12% weight difference when the boot is factored in. Big whoop! The convenience is worth it.
The biggest improvements on the '08 models is the redesigned closing lever, which has a new way of retaining the cable so it can't accidentally work loose (that seemed to happen once per day on the older models). They've removed the extraneous padding along the side plates that came unglued on my '05s, and reduced the amount of padding along the back plate. Setup is pretty easy with two different mounting plates to center the binding on the board, and qucik lean & tension adjustment using just a screwdriver and 4mm allen wrench.
The Cinch took some experimenting to learn the best way to get into it without sliding down the hill, but now i just dig my back edge into the downhill side of the snow and shove my foot in. The lever can be difficult to pull up, but if it is, I simply lean forward into the hill (Take a knee!) and reach back to flip it closed. But the new '08 latch / strap design is easier to grab and close compared to previous years.
All in all it's about 5-6 seconds to shove my foot in this binding, flip it closed, and I'm sliding! Great stuff!