I would agree with this. I don't currently have a commercial 21 because I have a 32" but I do have 5 (FIVE) 21"ers because of the reason for BACKUPS. I really don't trust homeowner 21's so I HAVE to have backups in the event that one or all dies I will have something to use. Good luck. and DO NOT gte a personal pace toro I had one lasted a week, wheel kept comin off.