One downside to a lid with a peak is it does catch the wind a bit which can straighten your back thus straighten your arms and cause a high speed weave. I suffer a bit with the high speed weave although it's not as bad now I've got a bigger screen on my bike. I am talking around the ton mark.
On a plus point, the peak is very good in low sunlight and it is good when you can see where your going

. The Arai Tour-X still looks quite good without the peak as well.
The best bit is it makes you look quite intimidating which I must add, so does the XTX (tall bike, loud, headlight set up a bit higher than it should be). I like scaring the cages around my way. Well it's better than them scaring me, innit.