to answer your first question about rooting...
I have rooted my android phone...samsung moment. and this did improve the phone greatly.
however... the reasons it did so was mainly because it stripped of a lot of crap sprint had pre loaded.
this tablet really is very stripped down as far as the software goes! it would be great to get a latter version ofnthe android os like version 3.0...but I don't think it will help performance. the performance issues I have are not really to do with speed. it runs pretty well even with it's measly 800mhz CPU....
what it lacks is the tegra graphics accelerator for video compression and decompression. and gameing.
and the screen sensitivity is crappy and I think that's just the way it's going to be regardless of software.
so I don't think rooting this will gain much performance as their simply is not much to take out of this device software wise!
buy as fast a class of microSD card you can class 10 is the fastest.