The most compelling reason to go with the ThinkPad Dock II would be to get the Ultrabay 2000 device bay and the half-height PCI slot. If you dont need either, then the Port Replicator II or Mini-Dock ...
I've got a new HP Zbook laptop. With my previous 9 year old Dell Precision laptop I had a dock where you actually lowered the laptop onto it and it locked in place. Looking at the options available ...