Coming from a former Honda small engine mechanic here, +1 on the Hondas. The HR-215 was an awesome mower. However, other models can work well too. Here are some of my observations.
I like the fact that Hondas have the BBC, rather than direct-drive to the blade, and the self-propel (which is a godsend for lugging around that heavy cast-aluminum deck) is powered via a small driveshaft with u-joints- no belts to wear out!
I don't know about the ones they are building now, but the Honda HR-216 a.k.a Harmony (10 years ago) wasn't a very good mower. They had issues with the early self-propel transmissions, and were recalled. The plastic fingers on the steering handle that hold the cable ends were prone to breaking off, and they had jetting problems with the carburetors (maybe not a problem for you as you've gotten practice rejetting KeiHin carbs on your monster bike!). The plastic deck is a plus, though as grass clippings aren't as prone to sticking and it's much, much lighter than the cast decks. Also, if you are going to buy a Honda mower, I'd recommend buying through a Honda power equipment dealer. The Home Despot price might be a bit better, but you'll get better service and have an easier time with warranty issues buying direct. (the local Honda motorcycle dealer I buy parts from also sells Honda lawnmowers and generators.. maybe you could get a volume parts discount if your local dealer does the same?)
The Toro mowers are pretty good too. They also have a blade clutch, but use belts and idler pulleys. The covers for the belts and BBC can be tough to remove after many years as the cast aluminum decks tend to corrode (they can't seem to keep the paint from peeling off the aluminum quickly) and the steel bolts weld themselves to the aluminum casting.
Snapper mowers are good, but the funky turntable system they use for the drive tends to eat bearings and make a lot of racket.
For many cheap mowers, they figure the engine will last 10 years with minimal care, and use steel that will rust though in about the same timeframe. If you take care of the engine, i.e. change the oil yearly, clean it off, service the plug and filter a Briggs engine will last just as long as a Honda. It may outlive the mower it's bolted to, though...
My 2 cents....