Perhaps the answer is not which to buy, but where to buy it from.
Love it or loathe it you do get some good offers on Ebay, but make sure you get a UK or Europe base map, a US version will be cheaper but and it is a big but once you are off the loaded map area tough.
Also if you are worried about paying a lot and nothing turning up, there are quite a lot of retailers who use EBAY and the prices are better.
Make sure you check the rating of the seller, a nice 100% is always good. Anyway back to the GPS, I started looking at the legend and then I saw the Legend C and that was it sold. My justification was I am only going to buy one so lets make it a good un. of course I then had to add the Autonavigation kit for another £165 but now I have a really good set up for in the car and of course for Geocaching