Storage is a concern. If you install programs of any kind or use it for web surfing, then the 32GB of storage that comes with the device will be filled quickly. Dont believe me, just go ahead and read all the topics we have on our site about people who have their SSD drives filling up quickly with minimal apps installed.
Pagefile, internet history, cache and so much more is also stored on that drive with a Windows based device that 32 GB can be eaten up very quickly leaving your device to suffer. As once you reach about 5% left of storage the system will start to lag greatly causing your streaming to suffer.
So yes, for a Windows based tablet you are worried cause if you are not, then you do not understand what happens with Windows when you start to fill up the small amount of space it gets. This is just a desktop version of Windows installed on these things. It is not optimized for tablet use.
I would seriously re-consider your stand point if you are looking at a Win7 Tablet. While I love windows, you WILL have issues with it. You will be back asking about why your getting lag and stutter when trying to do normal activities and getting disk low error messages.