Eh, I admit that I don't find the Spyder all that attractive, either. Oh, I love it *now*, but when they first came out I had ZERO interest in them purely based on its looks. Didn't see the appeal.
But, as the song goes, never make a pretty woman your wife...
(Don't tell my GF!!)
As for the Slingshot-- the big advantage here is that Polaris is not a boutique outfit. So, comparing it with competing niche 3-wheel manufacturers is (hopefully) a fool's errand. I can't imagine they're not SERIOUSLY focused on keeping the price low in order to establish a marketplace for these.
But, we shall all see soon enough!