I think I'll get one of the Waeco CF18s when it warms up a bit, best price I've found so far is just under £300, I'm sure you'll find a cheaper solution for weekends though...
Having used both types, I think the Waeco I bought a couple of years ago is one of the best investments I have made. It's great on the boat, but it's also useful off it. I have used it at Christmas for keeping extra frozen stuff, at parties for chilling booze and stooring ice, in the car for trips to the races, and No.1 son has just borrowed it to keep his GCSE art project fresh- a sculpture made from chicken bones! When he is as rich as Damian Hirst he has promised to buy me a Malo!