This is the fourth summer that I've been using the Fiskars reel mower. But as I posted in the "buying" forum, I'm ready to upgrade to a gas mower.
There are some nice advantages to the quiet reel mower. My 4 year old son has been able to play out in the yard while I mow and chase me back and forth without worry of a rock being spewed out by the mower or some other projectile. I can actually hear him as he talks to me since there is no roar of an engine.
However, after spending an hour busting my tail to get the whole lawn mowed, it looks ok, but there are still plenty of blades that either pass through or get matted down by the mower instead of being cut. While shearing is healthier than cutting, I can't say I notice a difference in the health of my lawn versus all my neighbors whole use gas mowers.