I have not used an edge computer since I like replaceable batteries and don't trust the edge's stability.

I've used a Dakota 20 and just a few days ago I replaced it with an Etrex Touch 35.

Both of them allow up to 4 data fields on the map screen. I think the Dakota 20 implementation was better though. In the etrex touch the fields are completely opaque, whether in the Dakota they had a slight transparency that allowed you to see more of the map. Really handy considering the limited screen size.