I'm actually considering their Conduit program that works inside Motion. It looks to be a powerful, but simple and quick alternative to Shake. Of course it's not as robust, but I'm hoping it'll be a good base to learn on and possibly change to Shake after I've got a handle on Conduit. Conduit seems to have a great keyer built in. They've got a demo of Conduit in action, and might be worth a look.
"If God could do the tricks we can do, He'd be a happy Man." - Peter O'Toole - "The Stuntman"
Machine Model: Power Mac G5
CPU Type: PowerPC G5 (3.0)
Number Of CPUs: 2
CPU Speed: 2.5 GHz
L2 Cache (per CPU): 512 KB
Memory: 4.5 GB
Final Cut Studio (Not Universal, yet)