I'm sure you realize this already but it's going to come down to dealer support and your personal beliefs on the two companies. Personally, I think these mowers have a similiar cut quality: the JD has 7-Iron II deck with a proven track record for strength and reliabliity even though their cut isn't always perfect; Ferris has the new ICD deck for 2010 which was released in some areas for review last year and has received really positive reviews for a clean cut and powerful discharge. I actually own a JD 757 (60" MOD) and a 777 (72" side discharge) which are being traded this year, replacing the 757 with a new JD 930A (60" MOD) and the 777 with a Ferris 3100 (72" side discharge). I'm staying away from the diesels in favor of a two year trading cycle and reduced capital investment, but both the Yanmar (JD 997) and the Caterpillar (Ferris) have great reliability records. One caution is to make sure you have a Caterpillar service dept nearby, because your Ferris dealer can't do warranty work on the Cat diesel (voids engine warranty) while John Deere can service your Yanmar without any issues. I hope this helps.