For an urban commuter, Marathon Plus is the nearest thing to a guarantee of arriving at work on time, short of solid wood "tyres". I hated their harsh ride and thirteen years ago moved on to Big Apples, on which I've had two punctures in that time, about the same as I had on the Marathon Plus in about the same period of time. For practical purposes that's a puncture-free cycling life. Both the punctures on the Big Apples were due to my errors, riding too fast through potholes or not making a jump onto a concrete step cleanly, in short, avoidable with more care. But I ride on pretty privileged small-town streets and clean if roughly surfaced tarmac lanes, so the comparison is unfair. The Marathon Plus punctures were the result of nails, which would have penetrated any tyre known to me. On the other hand, if there's no broken glass visible on any part of your commute to threaten soft sidewalls, you might consider the Big Apples for their comfort. There is no appreciable difference in longevity between the Marathon Plus and the Big Apple.
The Bontrager Hard Case Elite is a workalike, maybe even brand engineering, because they appear to me to be made in the same mold as the Marathon Plus.
Apologies if you know this already. Something not all Schwalbe fans are aware of: Schwalbe tyres are intended to be ridden until the protective underlay becomes visible.
I'd be very interested in your long-term report on the Greenguard.