Living in the city, my lot is a whole 1/4 acre, so I really have no need for a riding mower (tho there are hot days when I wish I had one! LOL).
That being said, for push mowers, my general rule of thumb is to go cheap. One of the best mowers I ever had was a Toro $99 special from Walmart. My buddy helped me adjust it to a higher revving idle (the factory idle was ridiculously low, to conserve gas), and the only problem I had other than that was that the stamped steel deck had a tiny hole that the grass clippings were supposed to go out through, which got clogged very easily. Two minutes with a hack saw took care of that problem, and I had a kickass little mower!! :awe:
Now, years later, when I bought the house, I needed a mower, and figured I'd go all out, and get a Craftsman self-propelled model, with a big engine. Big mistake was what it was! Less than one hour's use, and the self-propelled part of it broke! Called up Sears, they told me to bring it in for servicing (to the store), and I'd get it back in about 3 weeks (but it was covered under the warranty). Decided "screw that", boxed it back up, and returned it.
Went to Walmart, spent less than half the amount I had at Sears, and got a Weed Eater brand mower with a 5.25 engine......and it's been kicking ass ever since (tho I haven't needed it much this summer, due to the drought

).