Here's what I can gather from my Instant Watch Browser linking metrics (based on the first two characters of the SN)
Thanks for sharing the stats!
"N0" is Netgear NTV250 (2050N), a re-package of XD under Netgear logo that was briefly sold in RadioShack and online.
The popularity of 2 XS is "squawk"-explanatory. 1-XD on the other hand was middle-of-the-road but had the "new remote", wifi N and "the best HD" there is(n't), on top of which 1-XS was adding just dual-N (who?) and USB which was useless then for lack of channel (and now for the limited file format support).