I was never happy with the JD transmission, or the stink of the Yanmar diesel. I could have opted for the vertical exhaust kit, but didn' want the hastle of drilling a hole in the hood and loosing forward visibility. The Kubota hydro seems much smoother to me, and I love the new hi-lo lever on the stearing wheel. I do quite a bit of loader work, and having a 6-speed hydro makes for fast work. As for the larger JD vs the K 4720, I have read mixed opinions on the JD 4 cylinder diesel engine.