My opinion is that, for the vast majority of people, the GO 2505TM is the best Tomtom available without recurring costs. Of course it is also one of the most expensive Tomtom's available right now, too.
It has big pluses and big minues vs other models, but I feel that in total, the pluses on this model outweigh the minuses when compared to any other non-LIVE Tomtom.
We always recommend backups, since they allow you to self-recover from many crashes/bugs that otherwise brick a Tomtom.
Tomtom has promised that the MyTomtom computer software will eventually allow backups, but the feature hasn't been built yet.