I'm also six foot, and I have two minor visibility issues:
1. Looking forward, I need to lean forward very slightly to see some traffic signals. This isn't a big deal, as I needed to do this in my last two cars, too. (In the Miata, I found it easier when the top was down to look OVER the rail, rather than under it.)
2. Rear-view. The roof-line is a little too 'low', so I can't see very far out the back of the car in the rear-view mirror. This is a fairly big deal to me. I have come to rely in the side-view mirrors more, but even then, you don't see everything. What this amounts to is that I only see 4-5 car lengths behind me, which, to me, is a little dangerous.
(But I do like the placement of the center beam in the back, such that when a car is following at a reasonable distance, their headlights are blocked by the bar, yet I can still see their 'glare' above and below. And the lower window is tinted, so if someone is tailgating, at least their lights are a little dimmer than they otherwise would be.
The only other minor 'view' gripe is 'over-the-shoulder', those rear beams give the Prius a slightly larger blind spot than I'm used to. (Then again, a Miata with the top down has no blind spot, and one with the top up has a HUGE blind spot... Although I haven't owned the Miata in years.)