I'm not sure I can answer all your questions, but I can tell you why we chose the Meridian Gold over all the other Garmin units we looked at:
1. The Garmin units would never pick up satellite signals inside a store, whereas the Meridan Gold had no trouble. I spend lots of time in the woods, and our Meridian rarely looses the signal under tree cover.
2. The screen resolution may be a bit coarse, but when geocaching we usually are using a data screen for the last few hundred feet or so. We normally use the map screen to trace our path on roads on the way there and to navigate in unfamiliar driving territory. I have not been disappointed by the screen resolution.
3. We liked the idea of being able to swap and choose map data stored on multiple SD cards if necessary.
Finally, I chose a Meridian Gold over a Meridian Platinum because it did NOT have the built-in compass. This forces me to use a real compass, and we generally take paper maps as well for backup. There is no excuse for being lost in the back country because you are out of AA batteries.
Hope this helped.