Probably the Switch.

Essentially this.

Although if the game is bad I expect that will hurt PS4 sales not really the Switches

Sonic Transformers was a Wii U launch window release right? And it came before Mario Kart 8 so I think that would have definitely aided its sales.

It will be closely tied between Switch and the PS4. Switch owners have proven they like that genre of racing game, plus Sonic games sold better there, but PS4 has the bigger audience and Sonic Racing doesn't have that much competition there. Close, but I'd say the Switch version.

Despite the 80million PS4..... I would say the Switch

I'd say Switch but it really depends on when the Star Fox game comes out: if it's close to the Sonic release, then people might wait for Star Fox leading to lower sales

My guess is Switch. The types that like that kind of game seem more in tune with the Switch demographics. PS4 could give it a run for it's money by virtue of having roughly four times the userbase, though.

Naturally Nintendo Switch for a lot of reasons. But that doesn't mean much.

That's Starfox Grand Prix is even real. :P

Yeah, I think the ratio's will just go up further once it's released also. When all is said and done, expecting ratio's to be around -  3:1:0.4   (Switch, PS4, XBO)