It was the Trail magazine out now in the shops that did the 6 GPS comparison piece. YOu have a week to get it to find out what they reckon is the best.
I know a few people who have the satmap. IIRC there are two versions, well less versions more kits. One with a protective plastic screen cover and one without I think. I wasn't really listening to the guy telling me nor the guy next to him who also had his satmap out tryoing to get me interested in one. Zzzzzzzzz! Seriously there is nothing worse than a satmap bore. Anyway from the short period I was actually awake when they were talking to me about the satmap you want the active one and make sure you get the plastic cover. It is kind of a clear plastic cover with a frame to it that clicks into place on the satmap covering the screen in a way that makes it look like it should always have been there. Can be used without but it is £300 of kit so might as well make it stay fresh with the cover.
All good kit mentioned above so I think if you get up to the high £200s you will have something that will do what you want. Check out the lowrance kit. Lowrance in USA has a significantly higher market share than over here. IIRC Lowrance is actually a bigger GPS supplier than the main players over here with a bigger market share. They also make marine kit too including sonar, depth beeper thingies and fish finders as well as GPS units. As such they are a big electronics manufacturer. They also tend to be cheaper over here (or at least they used to be). Anyway when they hit the market a few years ago with a budget and higher spec GPS they kick started cheaper GPSs (without compromising quality and performance). At the time the budget Etrex GPS was something like £130 but the Lowrance equivalent (with 14 channels not 12 channels, more waypoints and routes that can be saved so slightly better specs) came out onto the market costing £89. £40 saving was significant I reckon and shortly afterwards the Garmin etrex was also £90. Made me curious as to how GArmin were able to make large savings on their units so quickly after a new (to our area market) competitor came out with a cheaper equivalent product!! If I was cynical I'd think they had a huge mark-up and were ripping off their customers, but I'm not a cynic.
Not sure about mapping but I'd have thought that a bigger name (garmin, magellan or even Lowrance) might have more chance of overseas maps than newer entrants like satmap but that is conjecture on my part.