This particular 680E is a nice example - Jim Metzger just completed a thorough annual back in August on it, including the installation of two fresh (AD free) Queenair props (Jim has the STC to facilitate the prop swap).
Jody has owned it for many years and had it based in eastern Washington.
The 680E has essentially the same fuselage dimensions as the 'Straight' 500 (both with bath-tub cowls) and also pretty much the same cabin dimensions as the later 'short' fuselage (slimline cowl) Models - 500A, 500B, 500U, 500S, 560F etc etc.
The 680E runs the supercharged GSO480 geared Lycomings and thus presents a nice performance solution for folk who are operating at high density altitudes and need to consider flying over mountain ranges and associated WX as part of their core missions - fuel burn is high.
The 680E is a 'sports car' and would be a challenge for an inexperienced ME guy - I would not recommend it as an 'entry level' twin.
The 685 was a much later and final attempt by the factory to re-engine (with complex pistons) and pressurise the longer airframe with the broad vision of enhancing and replacing the 680FL/FLP Models.