logical answer
To be honest with you I don't know a whole lot about the speed four, other than it's really popular in the U.K. and it's a wheelie monster. In other words a great trick bike, but so is the SV650S and there are just as many if not more aftermarket parts out there for the SV, if not more just tell your friend to take a look at svrider.com and click on the link to 2wheeljunkies.com. Also with price in mind the SV is cheaper without sacrificing quality and reliability. Trust me I've got one and it's bulletproof. I've had it for nearly 3 years. They're both not bikes you see everyday on the street. That's why I bought mine. Too many gixxers out there, I like them but I get tired of seeing someone with the same thing I'm riding. I want to be unique, I've got a full fairing kit from 2wj, seat cowl, harris grips, double bubble windscreen, micron highmount exhaust, carbon fiber trim pieces, bigger carbs, 1 tooth down countershaft sprocket, k&n air filter, and a small shot of nos. Point being I hold my own looks wise on the street because I have something you don't see everytime you hit the streets and I hold my own at the dragstrip. Most people think because there's no R on my bike it's not fast. That makes the look on their face so much better when I win, anyway your friend should also consider the price of aftermarket parts and the nearest dealership for Triumphs, you dont want to drive a long way to get your bike serviced. Bottom line both are good choices. Also if your friend wants a little more power he can always go with the SV 1000. Personally I would go with the SV, but I'm a Suzuki man, in the long run it'll be cheaper on your friend to get the SV to look the way he wants it to look, and the performance won't be that different. The bikes only as fast as the rider remember that.
