You may be surprised by the gas engines.  The Kawasaki's have been very good to us, which is the only real gas option besides Honda.  Kohler and Briggs are junk.  We have a Deere 925A and its been great with about 600 hours so far.  The two with the most units around here are the Deere and Hustler, both of which get about 90% market share.  Kubota is coming on strong lately and a few Exmark and Toros mixed in.