I have had an Mx5000f for about two years. The difference between the Mx and the 4900 is that the 4900 is and AG tractor. Heavier frame and the transmission is different. My shuttle shift is on the left. The 4900 is a GST I think. It shifts from a lever under the steering wheel. The 4900 can also be reprogrammed to 53hp. Or so I was told by the owner who was told by a tech at his dealer. I like my Mx I am clearing and maintaining 50 acres with it.. If I am not mistaken they both have the same engine or at least the same size block. I do wish I had gotten the 4wd at times using the loader. Get a toothbar if you get a loader with it. As far as power it has plenty for what I do. I bush hog up to 3-4 in. sapling with it.
Mike