I own a magellan explorist 210 since december 2005 and have some experience with it that i like to share.

Mapsend Basemap Europe.

The map for mapsend europe is a reasonable basemap to use with the maggellan.

My experience with it in the Netherlands is Good lots of information is on it and most of the information is correct

This goes also for belgium and france.

For portugal the map is somewhat outdated. A lot of new highways are not on it and also the road numbers are not anymore to what they are now.

Europe according to magelland does not include norway a big part of sweden and finland wich i do find disturbing, You expect if you have a basemap of Europe in it that it would include scandinavian countries.

Mapsen Worldwide Basemap

This map does include a lot of  information for the whole world so if you want some road information for for example Norway then this is a good solution. However Only the big main roads are on it and they are al lot of times not accurate drawn in.

Mapsen Directroute Europe

Directroute works perfect on the magellan explorist 210. I have used it a lot in Norway and must say that it contains a lot! of information for Norwegian roads. The smallest roads gravelroads private roads to houses forest roads all are on them. Allso the routing works good.

The only problem that may occur is, that the maggellan does not seem to see a good difference between gravel / privat roads and paved small roads. This means that if you are off the big main roads you might be sometimes directed to gravelroads that are or unaccessable or there is a perfect paved road alternative wich does not get the preference above the small gravelroad.

Geocaching

When you are a premium member of geocaching.com and use pocket query's read these pocket querys in into GSAK and then send them to the magellan as geocaches then this is a perfect instrument to use the magellan with geocaching.

You can allso use magellans own tool but with the GSAK tool you get a lot more possibilities. I use it in combination with directroute europe in Norway and let me direct to the nearest road via the routeplanner and then go to the cache. While going to the cache i use the tracking possibilities of the Magelland. This gives me the opportunity to go off the roads bushing my way to the cache wich is a lot of times neccesary to get to the cache.. With tracking my path i can easily after having found the cache go back to where i came from via the same route as i came to the cache. I have tracked walking routes from a few hundred meters to 20 a 30 km walking and it gives a detailed track that can be easily tracked back.

NMEA

Using The NMEA protocol to connect the magelland explorist 210 to a computer in order to see your position in programs like Directroute or Oziexplorer
or any other program that can read NMEA data

Via the menu on the magelland select advanced features/ communications/NMEA Data comm  and then usually the protocol V2.1GSA
NMEA  V2.1GSA 
The magellan will give out data via the usb port now.
Remember you do need a Sattelite fix in order for it to work!!!
The driver software for the magellan will simulate a com port on you laptop. In order to find out the port and the settings you can start the
program msinfo32.exe usuably found under

Accesoiries / System Tools / System Information

open components / modem and search for Magellan Explorist With device type External Modem. In the example picture it is connected to COM port 5

You can allso find the speed it is on wich is i think always 9600 / 8 / 1 No Parity

open components /Ports / Serial and search again for Magellan Explorist. You will find there the Baud Rate / Bits/Byte / Stop Bits and Parity

Set the port of the progam you want to use on these values and remember you need A 2D or 3D sattelite fix in order to have the magellan put out data.

Magellan & Ozi Exploer

I Have very good experience with using the Magellean Explorist 210 in combination with Ozi Explorer.

In Ozi Explorer you can download maps form your area by scanning paper maps with a regular scanner. However this requires a very precice scanning and reference coordinate settings. Me myself i got hold of 1:50000 topo of Garmin Mapsource and converted them with GpsMapEdit to ozi bmp format. those maps i for planning trips. I edit tracks and waypoints on them and upload them to the Magelland. And also I download Tracks and waypoints from the magellan to Ozi Explorer or export Geocaches form GSAK to oziexpoler format and display them in Ozi. The nice thing form Ozi Explorer is allso that you can export your tracks and waypooints to GPX files wich can be used to show thes in google Earth. In this way you get a nice 3D foto of your track and the area you walked in.