Originally Posted by KenshiBiker

At 10 mph I have the time to watch deer in the field, see the coyote running through the bushes, watch the hawk soaring overhead, etc. As I said, this is just me; if your level of conditioning and reflexes allow you to watch the scenery and wildlife as you pass by at 20 mph, more power to you.

Originally Posted by kickstart

It also depends on where one is riding. In cookie cutter suburbia it doesn't make much of a difference, but most places I ride other than my commute have a lot to be missed at higher speeds.
Our local MUT is mostly through wetlands with a lot worth seeing that will be missed if going fast. Sometimes I like riding it before sunrise of after sunset, I set my bars all the way up, use a high gear peddling around 30-40 rpm, at 5 or 6 mph. Having a totally silent igh bike allows me to sneak up on all sorts of wildlife.