I have a "D" model. The "D" and "E" models are, for all intents and purposes, identical.
These are the first models with a back window and a 1600lb gross weight.
The baggage area is larger than the earlier (fast-back) models, but smaller than all the slant-tails (I'm s-l-o-w-l-y working on getting approval to open up the baggage area to the same size as later years).
The doors are smaller and not bowed outwards - this makes for a slightly cozier cabin. Also, the doors and door-lock are flimsier construction, and tend to 'warp' and leak air at cruise speeds.
The manual flaps are actuated by a "Johnson Bar", like an oversize parking-brake handle between the seats. Quick and easy deployment and retraction, with five notches (0°, 10°, 20°, 30°, 40°).
The instrument panel layout is non-standard, though quite readable.
The pull-start handle is a direct line to the starter, making for an easy draw.
The straight tail (vertical fin) is a robust design with no ADs and arguably greater rudder authority than all slant-tails.
5" main wheels were standard; 6" mains were optional. Slant-tails used 6" mains. The larger tires are better for grass-strips, though I've had no trouble flying my 5" mains into a number of soft surfaces.
Frankly, when it comes to day-to-day flying the only big difference is the smaller baggage compartment. All of the other differences are minor. If the plane you are looking at is in good shape at a good price, it's worth getting, regardless of the model.
But you can't have mine!!