I've been using a Symap II (c. £400) for six months now in rented aircraft and love it. I strap it to my left leg and prefer the large size screen as it's easy to see at a quick glance, therefore allowing more time to look outside. Before choosing this one I got hold of the screen sizes of all in my price range and made little cardboard blanks to scale. The Skymap II was a clear winner here. The moving map is great after being given an ATC induced diversion and it's a fantastic back-up to traditional navigation methods.