One comment about batteries. I have repeatedly had issues with batteries vibrating in the unit and losing connection, causing the unit to power down or even lock up.
Sometimes, putting a foam ear plug in the case between the batteries and the cover would help for a while. This happened with the 276CS, 60CS, and even the Montana 600. It happened with the standard battery in the 276 and the Montana, and also with AA's in all three units. For this reason, I switched all units to being powered from the bike and have never had any further issues. Although, my 276 did eventually die
I use the Montana powered cradle. I have never had any problems with it even in very rough riding conditions.
I use the 600 for dual sporting. Sometimes the screen gets dirty. I just wipe it with my glove. If the screen gets messed up because of the touchscreen interface, I just hit the "return" arrow in the lower left of the screen and it goes right back to what I was last viewing. My biggest gripe about the touchscreen versus the rocker button of the 276/60 is that it is VERY hard to precisely location a drop pin or the cursor to highlight or identify something on the map, like when trying to pick a particular road. I have to sit and fidget with it, trying multiple times to get the cursor where I want it
It was MUCH easier to be precise with the rocker button.
As for being able to see the screen, the biggest issue is my vision, not the unit. I would LOVE it if I could make the fonts bigger. I have everything set as big as it can go, but it is still just a hair too small. I used to be able to stand up and see it better, but not any more...