SJ4000 is the best in the GoPro format for cheap. It's compatible with GoPro mounts. The quality of video is probably between the white and the silver edition. It's not the equal to the black, but the black is $400 and the SJ4000 is $120.

Personally I think the blacks are a ridiculous amount of overkill for daily commuting - unless you are also going to use the camera for something more demanding, or if money just doesn't matter that much to you, it's simply not worth the money.

The SJ4000 I think is at least the equivalent of the GoPro Hero3 silver (previous generation). Techmoan has a good review of it.

Personally I'm not a huge fan of the GoPro form factor, I'm not a fan of bolting bricks onto myself. I like the bullet format like the Sony ActionCam better, but I think I may pick up an SJ4000 as a rear-facing bike mounted cam.

My one suggestion would be, no matter what you get, make absolutely sure it has replaceable batteries. It's really nice if they're standard, the camera I currently have uses a Nokia cellphone battery. It would be awesome if all small consumer devices used a cheap, standard cellphone battery.