I recommend the D10-100. You can buy it (or one of the other models) from Valueelectronics, mention you are a member here for a discount.
BTW, as far as I can tell, all three run the same GUI interface (after updating to latest firmware my 100s and 200 have the exact same GUI, I don't have a 300, but I imagine they are too), the exterior is slightly different, but nothing to write about, the stability on the D10-100 is great, the 200 seems as good, but it seems D* is pampering the 100 over the rest since the recent update hit the 100 6/21 and the 200 did not get it till 1-2(?) months(?) later, and the 300 just got its update today.
Also I read the 100 serial interface works while the others don't (the new update may have changed this though, I myself have not tried the serial interface on any of the units).