+1 on the clear after dark. DO NOT get a visor that's too dark. It'll screw you up even if you ride under some trees.
My job sometimes requires me to stay until late into the day, so I carry my clear shield with me (I have a sack for it, and I tuck it into the waist of my riding pants. Rides nicely there, and doesn't get in the way.)
Anyway, I've got the blue mirrored one (BTW, yes, that's a Joe Rocket helmet... same shield. The helmet is made by HJC):
As you can see it's not TOO dark. Does a decent job.
I do wish it was neutral gray... it's brownish/amber. That's good for cutting haze and such (the human eye is evolved to be most sensitive to yellow light), but I like to see green grass and blue sky. You get used to the color quickly, and if your preferred sunglasses color is brown anyway, you're set.