For handheld use none of these.
Buy an iPAQ and install PocketFMS (
http://www.pocketfms.com/).
The software is free (although you can pay a once fee for slightly enhanced maps), it us updated every month, covers the whole of Europe and the maps are very detailed and of excellent quality.
The iPAQ offers a better colour screen than most dedicated units, is very compact (nice and easy to mount on the yoke for example), offers huge battery life with an extended battery, is crystal clear even in sunlight and works very well with a bluetooth GPS receiver. (so no messy wires or need to connect to the ships supply)
Most importantly, the whole package with a little searching on eBay is likely to be far cheaper
.