Now that I think about it, a Katana is probably going to require just as much maintenance as a properly sorted CB750. You lose the points, obviously, but you still have four carbs to synchronize and you have 16 valves instead of eight. I don't remember what the adjustment intervals were.
My first-generation SV was the S model, which has an upper fairing. I did thousands of highway miles on it, fully loaded down with luggage, and eventually sold it with about 30,000 on the clock. Rode several times to Arizona and back and once to New York and back. (Back being New Orleans.) The only problems I had were those caused by inept mechanics.
The Katana will have an edge for highway riding because it weighs more and has a saddle that is a bit wider. But the advantage is not as great as you might suspect. And the SV is better in virtually all other areas, in my opinion. On paper, the horsepower and performance numbers look similar, but from the saddle, things are far different.
If it was me, I would get a Katana if my riding was almost exclusively highway, or exclusively two-up or if I got a screaming good price. In all other cases, I'd get the SV. It is a far superiour motor, far better handling, quicker, easier to work on.
Is it possible to test ride where you live?