Hi folks,
I'll duck as I post this
I own a 25hp Walker with a high lifter on the 9 bushell catcher, very maneuravable, and the high lift was very good, But, these machines with their small drive tyres can't compare to larger tyres on the Toro Z 355, the Walker cannot handle slopes as well as the toro, but in tight areas and easy conditions a walker is great.
I bought a Z 355 Toro 6 months ago and to get back on the walker considering both cost the same, 2nd hand walker with high lift catcher was the same price as a new toro, is a weird feeling, one feels and looks and is built for commercial use, the walker is lighter, smaller, and the high set catcher even models without high lift are bulky and easy to damage, the toro is far better designed and constructed, unbreakable, go anywhere type of machine, and the mechanics are sooo simple, unlike the complex hydrostat system of walker's.
The catching system on the Walker is very dusty and dirty compared to the better sealed toro catcher. Toro blower systems don't block up like a walker's either, and very easy to clean. Exceptional fan!
Options, With Toro Z355 you get a deck that mulches fantastic, all I use, change baffles and you catch, equally as good as walker which is a leader in catching.
With a standard 48 inch walker deck you have a catching system only, the catcher blower always is on, more moving parts to wear, and if you want to leave the clippings you can buy a sheet metal attachment that keeps the catcher door partially open to spray the clippings out behind you.
The Toro options are better as you shouldn't mulch the same lawn all the time, you should do a clean mow a couple times a year, so the toro gives you 2 dedicated modes, and both are as good as you get.
And catching clippings everytime, been there, done that, and that's how you lose your profits, if you must catch, only dump on the clients property, I learn't the hard way, that's why I love mulching!
As far as build, you couldn't hurt the Toro, walker is very light, actually I call them light commercial/estate mowers, Toro fully commercial.
With a non or cheaply dampened steering linkage system like the walker you get super soft steering, but with those little gripless tyres you can scuff if not cautious very easily.
Catching grass on slopes is an interesting feeling with a high lift catcher walker, and going up a slope to exit with a full bin, hopeless feeling of no traction is a bit annoying, the toro just climbs seems to have more torgue, and those bigger wheels sure help.
Toro has hydraulic dampening, steering is a lot firmer making lots of fiddley work a pain but is better on the big areas as it tracks easier on it's own.
Toro you need to push the levers forward or back to get action like a midmount, the walker has a forward control lever so you push it like a throttle/speed control and use the levers just for steering, I do like that system, very easy to get used to.
Finally, the Toro is Far stronger built, better in my opinion hydraulic system, mulch/catch deck is excellent, and the grass hopper is far superior.
Walker, mine is an expensive back up mower, not used since I bought the toro. Lighly built which has advantages and many disadvantages, good around buildings, no good for fast open mowing, and to only be a catch mower makes it hard to justify the expense, when toro give you a mulching option which you will love and use more than you think.
Both cut great, Both catch clippings as good as the other, toro build is better, heavier steering, but gives you a total mowing machine, not a one mode like walker.
I know walker is the brains behind these types of machines and they make machines that cut exceptionally well and I believe also that other brands have set out to copy them, the toro z355 is the first good machine like this, they stuffed up on other tries but this model is a winner.
If you can, place both machines side by side, you will easily see why I bought a toro when I had a walker already, if you work on rough terrain, slopes forget walker, simple as that, only good on smooth mowing conditions and tight areas in my opinion as an owner of both comparing them as honestly as I can.
I am not bagging walkers in any way despite this comparison, it is only a friendly comparison between 2 machines built for different applications.
Please other walker owners, don't growl at me for these comments, your machines are fine for what you obviously use them for, I just prefer the toro, everyone to their own opinion eh?
The diesel engine in the Walker...in my opinion

The engine will outlast the machine easily. But I wouldn't go for a diesel in this size of mower.
Regards,
Tony