Hey Captain,
Just wanted to let you know about a couple different types of mowers,check out grasshoppermower.com as well as cubcadet.com,these two brands are about the best you can buy for very heavy personal or light industrial use if you go with there higher end units.I have a quite a bit of rental equiptment experience and can tell you first hand when it comes to small engines you cant beat the honda engines especially there gx series which are in my opinion the most reliable on the market.But the kohler has proven to be just as reliable with a better multi stage air filtration system on there higher end units which is just awesome.Also I have only dealt with the kubota gas and diesel engines on a limited basis to date but they have also proven to be extremely reliable with a very long service life claimed on there diesel powerplant.The main engine I would tend to steer away from would be the briggs,they have gotten better over the years but are still lacking compared to the other brands mentioned,althought they hold up pretty well if properly maintained.Anyway I dont think you can go wrong with the cub cadet or the grasshopper,personally I prefer the grasshopper just because they tend to have beefier chassis,components and better quality bearings throughout.Anyway I hope some of this might be a help to you,if you need anything let me know I might be able to help out.Good luck,Nick.