(*Also have Memory Map sw on pc)
I've just gone from basic Etrex (which gives Grid Pos, tracking and direction pointer on a preloaded route, to a Satmap (rolling OS50,000, tracking, routes, dancing, singing etc etc). I found the Etrex sometimes not quite accurate enough (in areas of busy tracks/multi junctions) etc etc you could go wrong blindly following the arrow,however in combination with OS Map and grid ref you can sort it out. I really thought I'd love the rolling OS but I don't, possibly as the area size displayed is very limited and possibly after about 40 years of reading OS50,000 full size I might be 'habitualised' or something (and poss as the map can be twisted, moved, etc etc very quickly) and you can see distant reference points and line the 'world' and the map up.
Ultimately I will always have a map and compass anyway, the Etrex sometimes helped out (ie New Forest, where no decent reference points, NW Highlands - so many bleeding peaks it was impossible to be definite) and the Satmap was bought for Scotland as I am doing all new routes and don't want any disasters, but to be honest I don't think I need it.
Both can be uploaded (via .gpx etc files) routes from the tinternet, which is a definite advantage.
I actually find memory Map the most useful thing, you can get the route distance and profile immediately so you can easily size it for you (*track conditions excepted)
Given your points I'd certainly try before buying esp satmap as they're jolly expensive...