Of all the vehicles to altitude that I have been blessed with the opportunity to leap from, my favourite to date I think has been the Lockheed Super Constellation. Doors on both sides at the rear of the plane, exiting at the speed of a small jet. My first skydive (a static line round parachute jump made on October 6, 1991) was made out of a Skyliner — like a Skyvan, but with the exit being a side door rather than a rear ramp.
Here at Zephyrhills during the Christmas boogie, they have 3 Otters (a left hand wide door to exit from), 2 Skyvans (a rear-facing ramp that one can run and dive like superman from) and a local visiting helicopter that takes jumpers to an exit point of 5,000 feet for $58 . Wow, what a selection! Spoiled skydivers we are :).