Just sold my Satmap & got an Edge 800. No contest as far as I am concerned although my Satmap was the earlier (not plus) version.
For me the Satmap is heavy, you can really feel it when it is mounted on the bars
Lets water in between the screen protector & the main body of the unit,
Not great battery life,
The button menu access isn’t great,
& most importantly is hard to use on the move: The lack of turn by turn directions is a serious difficulty for me. The line of route marker obscures the detail of the map so that when you get a difficult section you can’t see what is going on. I found it was great as a map – to show you where you are- but to tell you where you want to go? I find the Edge is far easier to use. Although the Satmap screen is bigger, it still isn’t big enough to be useful if you want to get an overall of what is around you. I think you realistically need a screen the size of an I-pad to get what you get with a paper map.