Marcy,

Well, no, I've never even seen one. But in general, though my computer is convenient for guaging my riding, I've
found that it's sometimes more of a distraction than anything else. If I look down to see how fast I'm going, I
start to slow down, and plus I don't like taking my eyes off the road like that. When I use it to check my mileage,
I find (since I commute by bike) that I already guessed about how far it was anyway. If I want to pay attention to
my riding (which is advisable in traffic), I just do that, and concentrate on how I feel on the bike.

Pete Clark