Also note that if you have a laptop that supports Thunderbolt, you need a docking station that supports Thunderbolt. If you have a laptop that supports Alternate Video Mode, you need a docking station that supports Alternate Video Mode. AFAIK no laptop supports both modes, and very, very few docking station supports both. (you'll usually get reduced features if you have a mismatch; for instance, you'll get just one monitor, or two monitors at low resolution, or no video out at all, just the additional USB/ethernet ports)
My work laptop has Thunderbolt, my personal laptop does not. So this is an issue for me. I have a Plugable TBT-UDZ, which is one of relatively few docking stations that supports both. I can therefore use two 2560x1440 60Hz displays through either laptop.
This isn't without issue. My work PC (Windows) will every other week or so BSOD when connected to it, but, well, it's Windows. My personal personal computer (linux) will not crash, but every other week or so will simply refuse to recognize the docking station. So I have to unplug the docking station and plug it back in. It's annoying, but not the end of the world. I believe these two issues are the same issue, but I haven't bothered to confirm that. I don't have a Mac to try it on.