The SV650s is more of a starter bike... what I really like about them is the aftermarket support. They are bikes that grow with you as your experience builds...

The I4 600 SS are already where the aftermarket can take an SV650s, with more HP to boot. You can make a SV650s fast but it'll take some money to make them anywhere near a I4 600.

In the handling dept, with USD Full adjustable forks & rear shock the SV650s should be as good in the tight stuff, if not better... but stock for stock... the SV650s is no where near the same league...