Hi, my first post here, so please be kind!.
I'm at Disney at the moment, and am able to comment on some of topics you have raised. I'm a bit of a "geek", and "can't be without Internet", so I've some experience with broadband over "mobile"/cellular, including Virgin's MC760 (Virgin USA, that is), as well as it's limitations and some of the ways to work around those.
Shortest answer: the MC760 on virgin works in at least one room (mine!) in Bay Lake Towers, and if that (MC760) is what you already have, and want to use on a Windows based desktop/laptop/netbook, it will do fine.
Medium length answer: As above, with: if you haven't yet bought your MC760, or can change it, and want to use VirginUSA's mobile broadband, you might want to change the MC760 for Virgin's mi-fi device, if you want to have use of any of a) more than one device at a time, b) a device that doesn't have a USB port (such as an iPad), or c) a Mac.
(Possible disadvantage for the Virgin mi-fi ; it is 'locked' to Virgin).
Long answer, if you have made it this far. I have an MC760 on Virgin (USA) I bought 2+ years ago on visiting the USA. One of it's disadvantages is it can only be used on one device at a time, and it wasn't very 'fast', and can't be used directly with an iPad so I didn't use it on 2 previous trips, electing to use a combination of a GSM cellular phone as a 'wi-fi' hotspot, and a portable travel router in the hotel room (converting the room's wired broadband into wi-fi). This trip the previous cell phone plan I'd used was no longer available, and I needed Internet pretty much from the moment we landed in the USA, even if it was on just my Windows laptop, so I looked again at the MC760 ; advantage : it could be reactivated even after over 2 years (and from outside the USA!).
This would save me having to buy a new device, but didn't overcome the limitations above. However, I didn't want to buy the Virgin mi-fi, which would overcome those limitations, as it is 'locked' to Virgin, and there is a way to get around the MC760's limitations.
On a previous trip I'd used a travel router, but it was only compatible with an old security standard (WEP only, for the geeks), so I'd found a new travel router with better (WPA2) security. This router also has a USB socket, allowing for cellular modems, leading to : could I use this with the MC760? - yes, or at least ; in theory yes, as from the hardware compatibility list, they are compatible. The newer router I am using is a Zoom 4506, by the way.
Wired Internet is $10 per 24 hours at Disney (on-property) hotels. However, it is free for DVC (Disney Vacation Club) guests, provided they are staying on their DVC points. The travel router converts this wired broadband into WPA2 secured wi-fi. I can then also use the Zoom travel router while "out and about", using the MC760 to provide the data connection only while away from the wired connection (the wired connection is way faster!).
As the Zoom isn't locked to any network, I can use it with the MC760 in the USA, and a Huwaei mobile broadband dongle (via a different cellular provider) in the U.K.
The Zoom is powered by an internal battery, which has spares cheaply available, so I have a 'backup" battery as a spare, too.
The MC760 has now had it's limitations circumvented, and I've avoided some of the limitations of Virgin's mi-fi, too, so it might be worth considering if you already have the Virgin MC760.
Initially, I couldn't get the Virgin MC760 to work with my Zoom 4506 (in fact it was searching for the 'fix' that lead me to this thread). The solution: if you need to manually configure the MC760, the "number dialled" by it is "#777". I hope you find this information useful.