Ok Let's be real the 5085 M is so vastly different from a 5085 E that I don't know where to start. But I will try.
The 5085 M is 2013 Technology the 5085E is a 5420 or 1998 Technology( I am not saying which is better Just they are different, I prefer to move forward)
The 5085 M is a mid frame tractor, the 5085 E uses the engine and tranny as a frame. So the M has much higher torsional strength in loader and twisting applications on uneven ground. The mid frame is also helpful when splitting the tractor and other maintenance.
The 5085 M has Larger Rear axle housing and larger components made to handle heavier duty applications. Both are made in China but the 5M has a USA made Transmission
The 5M has synchronized ranges the 508E does not. That is a huge help in transport and it shows how much better the new Transmission is over the old. Syncro ranges is huge.
The 5085 M has EH 3 point hitch controls which is a huge benefit for precise and comfortable work. It also allows a very quick raise and lower for working with tillers and mowers. I find I cannot live without EH 3PTH, I did for many years with my Kubotas. Frack that
The 5M series has Radial tires as a choice, so much better for wear and field apps and ride if you transport your tractor much.
The 5M series has 20% higher implement flow which will help that loader cycle much faster.
The 5M Deluxe platform is truly flat and suspended so it is much more comfortable than the 5085E.
The 5085M has the PVX engine 4 valve per cylinder and the same as used in the 6M while the 5085E has the Powertech E engine. 2 valve fixed turbo, you get the idea. 2005 vs 2013 again.
The 5M has 25mph transports speeds available the 5085E goes 17mph, huge for transport from job to job or field to field.
The 5085 M has remote 3pt hitch controls for easier implement hookups, and a better sway control system than the 5085E
These are real substantial differences and well worth the extra cost if, speed and comfort are important. Oh the 5085E is a great tractor and it is very good looking. It can do everything a 5M can do and alot cheaper, but never kid yourself the 5085 M has the strength features and ability of a much better tractor at a good price.
As for the guy who was talking 5065E You are looking at a 5003 tractor in essence and it is a great tractor but it is Old Tech, no comparison whatsoever to a 5065M or the 5085E