I have a Curvey my better half has a K5. I've ridden both bikes alot and IMHO the power delivery of the carb'd curvey is slightly smoother but you really have to look for it to notice it. TBH I find the fuel injection smoother on the K5 SV than my K5 GSXR is.
The one benefit IMHO the K3 onwards bikes have is that if you are an all weather rider you don't have to suffer with carb icing in the winter. Its a right pain in the behind. You can do things to sort it but it involves either spending money on more expensive fuel i.e Shell Optimax or a fuel additive.
The seat is a bit hard to start with but it does break in over time.
The fuel injection, different pointy frame and bodywork are the main differences between the two types of SV. The K3 onwards make a little more power as well.
They work with a race can just fine.
