Power is Mustang 410BHP versus 345BHP.
The RS should be quicker to 60 due to traction, the Mustang is quicker to 100 and beyond 100 the Mustang is gone, though if you want to go crazy beyond 155mph the RS will be coming back as then your in the Mustangs overdrive (6th) which is terrible for acceleration on stock power. Roll performance the Mustang wins. Twisty road in the dry they are both very good but the RS is easier for sure, in the wet RS all day long!
Mustang feels nice inside, materials feel nicer, seats are comfier and seating position is just better. Focus is dull and boring inside but is actually put together OK, I was not much for the seating position however it feels well high, I had the seat as low as possible and still felt like I was on top of the car. To be honest the RS is a great car amongst the other new cars available, but sorry to RS owners, my EVO X was simply a better car, it handled better and was even more practical and I even prefer looks of the EVO and they are very rare sights on the road. Seeing several RS everyday, Mustangs are still a rare sight as it seems most have being purchased to be garage queens in typical Mustang fashion.
For me starting the RS was well like starting any other car, it did not feel special. The Mustang simply has a real special feel to it and starting it and that V8 springs into life. But some people get this and some do not.
The Mustang also gets great attention from all kinds of people and its positive attention, even today there were some people in our showroom asking the staff if someone here owned it and if they did would they mind starting it up. Of course I obliged, never need to give me an excuse to go and do some revs.