If we're shooting for apples to apples, shouldn't the Stephenson's 2R be compared to the winter version of the Montana, which is listed as 3 lb. 15 oz. and $496? This puts the 2R at same price, lower weight, higher wind/snow potential I think, though not as much as it appears, because the Stephenson's weight is sans stakes and sealant. Trail weight of around 3 lb. seems to be common.
Granted, I've never used or even seen a Montana 2P, and in re-reading the article, the "winter-lite" comment isn't clearly attributed to a particular set of options so perhaps the Montana can be configured to a truly 4-season setup? But I guess I still don't see, from the numbers at least, how comparing the Warmlite to the 2 lb 10 oz configuration is apples to apples.
Of course, there are other considerations, like the 2R's lack of a vestibule which would distinguish some apples from other apples or whatever, but I think "lightest two person double wall four season" was the part that sparked the debate.