Processor. Screen.
In a year the 2133 will be old hat. From my experience in gadget
buying, buy the latest technology so you won't have the urge to
replace it within a year at least.
Plus i have always felt 10 inch is the ideal screen size for this
category.
And i got a great deal what cn i say :D
I don't mean to pee in your Wheaties, but the 2133 has actually a higher-res screen AND a better processor (IMO).
1000 = 10" WSVGA (1024x600) resolution
1000 = Intel Atom 1.6GHz
2133 = Via C7-M 1.2GHz
The Intel CPU has a faster clockspeed, but it isn't significantly faster than the Via unless the application you're running supports hyperthreading. The Via proc, on the other hand, is MUCH more power-efficient than the Atom, meaning those meager 3-cell batteries will last quite a bit longer on the 2133 (plus less power consumption for the smaller screen).
All told, I think the 2133 is the better unit, despite it being "older" (not everything that's newer is better).