You probably do some sort of filtering on the raw input, maybe some sort of landmark based SLAM.

The factory calibration on the 64 diodes of the velodyne is bad. It needs to be fixed. There is a paper out of Stanford that tells you how to fix it. I can't think of the name off the top of my head but if you email me I can dig it up.

Also the error grows with distance. So if your bot is navigating off of objects 200 meters away, yeah you'll be more off. But you can use points closer to it and you'll get better results. Look around and you'll see that the velodyne has been made to work. Nobody loves it though.

The riegl has very low beam divergence, is beautiful, survey accurate, not waterproof and $300k+.

Don't forget the workhorse SICK scanners. They are cheap and have their pros and cons.