I have had all 3 and all excellent but have just gone back to the 800 just because the mount is better and the battery lasts all day even with the back light on,but for multi-day the oregon will be excellent as like you say you can just pop some battery’s in,if you need a garmin discoverer full uk OS 1:50K map I have one for sale it’s just plug and play so will work on any £45 posted.