Sorry to hear you got a less than adequate response. I'm a researcher at MS, and I developed the anti-ghosting tech in the X4, so I'll try to help.
To answer you first question, the X4 uses a Fast USB interface. This was going to be the highlighted feature before we figured out the anti-ghosting thing. I didn't work on that part, but maybe I can shed some light on the issue. Just because a keyboard does fast reports does not mean that it responds quickly to a key press. Switches bounce, and ESD (electro static discharge) events can look like very brief key presses. To counter this, keyboards typically require a key state change to last for some amount of time before assuming it is true, and reporting it to the PC. On top of this, there is considerable lag on the PC side in doing something with this data. If you are looking for something to happen in response on screen, that adds a lot more time (frames are only updated every ~17ms on a 60Hz display). The bottom line here is that you shouldn't put too much stock in a report rate number - the situation is just more complex than that. For what it's worth, I believe the X4 issues a new report every ms or two. But I just don't think that tells you very much, and I'm kind of glad we're not distributing misleading information.
The anti-ghosting on the X4 is unlike any other keyboard, and I would immodestly argue it is one of the very few true advances in basic keyboard technology in many years. Standard key matrices have certain key combinations that are ambiguous - i.e. you can't tell electrically which keys are being pressed. This problem starts with some combinations of as few as 3 keys. (Not all - something less than 5% of them typically.) Often, when manufacturers claim to have partial anti-ghosting, they actually mean that the attempted to move the bad combinations to less used key sets. It's the electrical equivalent of sweeping the dirt under the rug. In contrast, the multitouch-based technology in the X4 can theoretically see every combination unambiguously!
Of course, there are caveats. Just because the keyboard can theoretically see any combination of keys doesn't mean that you can report all of them, or that the operating system will handle them properly. We put together a detailed info site that explains ghosting and tells you precisely what the X4 can and can't do. It is here:
I think you'll find that the info presented here sets a new standard for gaming keyboards. (In a nutshell, the X4 can report 17 arbitrary keys, but that doesn't count things like the Media keys, or the macro keys, which have separate constraints. Essentially, it makes ghosting a non-issue for 10 fingered gamers.)
We are very proud of the X4 because it is the first gaming keyboard to have true anti-ghosting technology at an affordable price. As far as I know, there is nothing even vaguely comparable anywhere near its price range...