I researched all mower brands recently before i made a purchase. When i say "all" i mean the major players like Ferris, Exmark, Wright, Gravely, JD, and on down the line. Probably 10-12 brands. Most of the brands have their strong points. When it comes to engines though Kawasaki is what you will find on most of the better mowers, for good reason. When compared to Briggs and Kohler, Kawasaki has by far the most durable air cooled twin on the market today. The rest of the mower has to come down to what your looking for as each brand has its strong points. The Ferris line is known for its full suspension, which is great, if that's what your looking for. The gravely's ride is more like a tanks than a Bentley's due to being built heavier overall. Which one will last longer IMO will, like most everything else, depend on how its taken care of during its life. All that being said, The Gravely today is the better built machine. Years ago Ferris was bought by simplicity which in turn was bought by Briggs and Stratton. Since then then all of the Simplicity and Ferris products have gone down hill just like the Briggs engine.