There was something on this vehicle a while back in SnowTech Magazine (snowmobile technology). It makes sense for Polaris to do something different like this. Where the Spyder was BRP's entry into the street-legal market with a safer motorcycle, Polaris already has street-legal bikes so for them to come with a Spyder clone would cannibalize their own Victory and Indian sales. So instead, they apply their popular side-by-side layout and go after a different crowd.
I do not see this vehicle taking much away from bike or Spyder sales, very little. I believe it would not appeal much to those who ride sleds, bikes, ATVs, or PWCs. The appeal would more likely be to current side-by-side ATV owners (which Polaris OWNS the market share in) and seeing how this is a sit-in vehicle with a steering wheel, they could be going after some convertible owners.
The main benefit of the three-wheel configuration is getting around the automotive crash and safety regulations, so legally it is going to be considered more of a motorcycle, which is kind of funny. The Spyder is a safer motorcycle, where I see this new vehicle from Polaris being a less safe car. Sitting this low, it will hide behind other vehicles and it will be hard for other drivers to see it.
The driving experience is going to be far more go-kart like, as you will drive it instead of ride it. You sit in it, not sit on it. It will be far less rider (driver) interactive. But, it will be fun to drive. The concept of having a cross between a go-kart and a convertible in a three-wheel arrangement is pretty cool. My guess is the popularity of the Spyder got under the skin of the brass at Polaris and, looking into the Spyder patents and their own product lines, this was the way for them to go.
The key will be the retail pricing. My guess is 30 grand. Sounds like it has a GM 2.4 litre Eco-tech (too close to E-TEC?) engine with about 200 HP. At this price it might never be more than a boutique vehicle, but who knows, with ATV side-by-sides going for almost $20,000 what is another ten grand for that crowd?
Also of curiosity, in this thread was a post by a member "dascrow". This just happens to be the same name as the administrator of the slingshotforums.net website. Interesting.