I got a ZTR about 5 years ago and wish I'd done it sooner. They're a little faster in general on wide open areas, but it's more than that. My knees took a real beating on velkies and when walking. I find riding much easier. Even standing on a sulky, you are still having to support and balance your body weight constantly. On jobs where I used wb's, the parts where I got to ride felt like I was taking a rest break. Wb's have their place, but not on 1-3 acre properties. I agree, a 48" to 60" rider (smaller ones are more versatile but you lose productivity on larger properties) and a 32" to 36" (32" if you do a lot of small gate properties) wb make a great combination. Besides, you will need a backup anyway, so get one of each type, with deck size on each determined by what props you're mowing. And of course Wb's are often needed for steep slopes, places ZTR's won't get to for whatever reason, and for mowing wet turf or soggy areas where the ZTR tears it up.
Remember, if you aren't using the wb full time it will last a long time, and the extra cost of a 2nd unit will make you much more efficient and will more than pay for itself. Compared to the lost income from being less efficient, these machines are dirt cheap, even though it may be daunting to think of buying them now. I enjoy mowing with a wb and sulky, and think it is easier on turf in many cases, but it's much more wearing on ME.
