It looks like they try to advert this protocol as the better one and the examples shows some latency.
For Windows this may be true regarding MME (WDM is really faster and likely less latency differences between LTB and WDM would be noticable), for Mac and Linux, LTB would not make a real difference as those systems have low latency communication with external MIDI gear. Perhaps if you would have a lot of midi devices, it would make some difference but then all those devices should support LTB as well and that is probably where the limitation starts.
For the VST protocol, there is an SDK freely available, yet for the LTB
protocol i can’t find any stuff.
I know you have to carefully watch out which chipset your Main board has, but other than that you can better rely on the answer of users that have a USB MIDI device.
Seaquest : If you can get hold of one, try to find a Edirol UM-880. Unfortunately it has been discontinued, but Vista drivers are available. A very competent MIDI-interface anyhow.