Which bike you like best will ultimately be only your decision. But if you already know you prefer the riding position and the engine size, then your off to a good start. The I4 will have different characteristics, less low end torque more top end power and range. I haven't heard any complaints about the suspension just wearing out on the FZ6, like I've heard of with the SV's. SV's are also way to common for my liking.
I had a SV rider I meet last night tell me he'd tried an FZ6 once, and thought it had very very upright positioning. He said it was "just like riding a scooter, a 100hp scooter".
So there you go, opinions WILL very greatly. Only yours will mater in the end.