I own a Teryx, and only use it in the sand, about 80 to 100 days a season. And I enjoy the crap out of it. I left it a 2 seater, but enjoy the use of the bed. Few safety mods, and comfort mods.
We have all makes and models in our group. Including the rzr and the rzr s. If you truely are looking for a 2 seater for the sand only and dont care about a bed, etc.
Go with the rzr s. Its a great lil duner, stock.
And im not a monster fan of Polaris, but 2 seater, duner only, bang for the buck, go with rzr s.
I drove a rzr s in the dunes, other than the actual size, (I a big guy) it was a blast!