I've owned the Mast-R-Lift for a couple of years and love it. Comparing it with the new one, the only significant difference I see is the adjustable "jaws" for different riameters of routers. The original came sized for the PC 7518 and you purchased "adapter sleeves" for smaller diameter routers.
The II also appears a better fit if you're going to be swapping the router in and out of the lift. The original, while you could remove and replace the router, wasn't set up to do it quickly. Bolts instead of cams, etc... For a permanent mount I like the original as it is more permanently mounted.
Check out that new high-tech cordless router.. wireless and no recharging required!!