I prefer walkbehinds. One of my reasons is I could not use a zero turn on most of my properties. I have a few slopes that a zero would fail just on the approach. If I have a employee that says they reuse to run a walkbehind because of the abuse, trimmer and edger time it is for him. Then again, I am somewhat consolidating this year and going solo most of time.
I have found the maint. is easier on walkbehinds as well.