Have not ridden both but own a Stryker and sat on a Raider multiple times. From Star's website the Raider obviously has the bigger motor but is 84 lbs heavier, 2.5 inches wider, 1 inch higher seat and overall/wheelbase is right around 2 inches longer.
It could be the handlebars etc. but on the Raider my arms were locked and stretched and I'm 5'11" with a 32" inseam. I can flat foot both easily but I just don't think I'd enjoy the Raider's stock ergonomics and have to drop cash into the bike to make that work.
So... I guess it comes down to the motor as being the biggest difference for me and I still have to ride one to actually feel the difference but on paper converting things to a power(actually size since I don't know the HP for each) to weight ratio gives the Raider the advantage at 2.54 cc's/lb verses 2.02 for the Stryker. What that equates to in the real world is lord knows and of course mods can up the ante for both bikes. Even stock the Stryker moves me around fine for now.
Like others have said, they look similar and are both good looking and good values. I hope other manufacturers keep up the good work as well. Competition is always good for the consumer