I could not agree more. John Deere AG equipment, with a few glaring exceptions, holds its value as well or better than any other AG equipment.
When I was debating on buying a new tractor, I test drove them a bunch of different brands: MF, NH, CIH, CAT, Zetor, Same, Kioti, etc...
My final decision came down to JD 5420 and NH TN75A due to value, features, quality and resale value. The JD won out due to that last item. Resale value. I watch auctions and dealer inventory like a hawk. JD 5420's are selling for as much and sometimes more than what I paid for it 4 years ago. You can not beat that with a stick! The NH TN75A's and CIH equivalents have depreciated 35-50% in that same time period. The Zetor, Mahindra, Kioti, and other brands (except Kubota) have depreciated 50-75%. In some cases they are all but giving them away. I can not comment to MF and Kubota because there just are not enough of them around this area (or maybe I am just color blind to red and orange).
I attribute the value of JD equipment to three things: reliability, availability of parts (seemingly forever) and dealer support network. You know it will work and if it doesn't you know that you can get it fixed. The exact same thing can be said of JD & CAT earthmoving equipment. I can still order parts for a 1940's CAT D4 and get it the next day! It may be a little more costly than a modern part, but cheaper than buying a new machine.
Ask anybody who purchased a Belarus how it feels when a part breaks and no spare parts are available. Then you will see the value of the JD system.