I have a set of Napoleons that I am really happy with.
On the stock bars the visibility is night and day better then the stock mirrors.
I have also used them with the low cafe bars from NewBonneveill.com, and the visibility is great. I now use them with clubman (Ace) bars. The visibility is not as good as the previous sets of bars, but I love the way that they look.
I have had them for about a year and a half, and there is a little pitting and rust on them. If I took the time I could probably buff that right off.
Overall they get high marks for function, and higher marks for the way they look.
It may or may not make a difference to you, but they will definitely make you think twice about lane splitting.