I bought the original Surface Pro when it was released and since then I have been in search of docking solutions.
I have tried the Lenovo USB 3.0 dock which includes dual DVI outputs. However, it had horrible mouse performance and when I moved to a Dell U2913WM (2560x1080) monitor, it did not support DP or the higher resolution.
I also tried the HP USB 3.0 dock which had better video support, but also the mouse would lag and sometimes the video would glitch.
Next, I purchased the Dell s2340T monitor home, which includes a USB 3.0 dock. Again, the mouse would lag.
All three of these devices utilize the DisplayLink USB 3.0 technology. The problem is that you are trying to run video, audio, network and mouse/keyboard over a USB 3.0 connection. DisplayLink updates their drivers regularly, but in my experience, every release has it's issues. The mouse lag on my Dell disappeared when I installed Windows 8.1 preview and the DisplayLink beta drivers. However, the lag returned somewhat when they upgraded the drivers to RTM. During this whole time, I was never able to play encrypted content (Netflix/Hulu) in Windows 8 store app (metro) on the Dell monitor. Recently DisplayLink told me that the monitor did not support it. We also had issues with encrypted content with the HP and Lenovo docks, but that's been long enough ago that they may have resolved those issue with updated drivers. For a while we couldn't play encrypted content in a desktop browser with the DisplayLink drivers loaded.
I finally said forget it and just used a DP cable, a USB3.0 cable and a power adapter at work. For one extra cable, I got excellent video quality and excellent audio over DP all with not issues related to DisplayLink. At home I stuck with the Dell monitor/dock because it also included touch. After one update that made mouse performance worse, I uninstalled the DisplayLink drivers and went with a three cable setup there also.
Now, when the Surface docks became available I purchased two, one for work and one for home. No regrets. The network adapter is only 10/100 but is adequate. I have USB3.0 to GB adapters and could use them if needed but really for what I do, 100mb is adequate. DisplayPort on the Surface Pro 2 is 1.2, so you can daisy chain supported monitors. My Dell U2913WM monitor has a built in USB3.0 hub, so USB ports are not really a problem for me.
The Surface Dock is much better than cables and is much more solid than any of the DisplayLink solutions I tested. Plus I can actually play encrypted content on my very nice monitors.
Since the Surface Pro release, I have been using the Surface Pro as my primary computers at work, home and on the road. It makes an excellent desktop when docked and makes a great if slightly heavy tablet. As a laptop, I find the screen a bit small for my eyes. I have now purchased the Surface Pro 2 and love the new type cover 2. If possible, I will keep buying Surface Pros until they quit making them as I can only see them getting better and better.
For the record, my job includes evaluating new technology for my company. This gives me a flexibility that others would not have and would find cost prohibitive. We have enough employees that most of what I get can be handed down. By the first of next year, we will probably move forward with deploying Surface Pro 2 tablets (or an equivalent) to current laptop users.