Just joined, lots of usable info (too much really!) as for the 21" trim mower debate, i've got to support jones. You don't need to be a rocket scientist to know a bigger mower will cut more grass faster, but in the 'burbs north of toronto anything over 36" wide is often useless in a significant number of backyards. either the gate is too small or its just not worth the time. Most lots we do are about 60-80 feet wide and 130-180 feet deep. with lots this size a crew of 2 can knock of 20-25 or more a day with two 21 inch mowers. Having said that, just picked up a 33" walk behind mower new to dealers in this area and it seems to be the perfect compromise. Pushin 30+ houses a day, sleeping like a baby at night.