I've been holding out from the smartphone revolution for quite a while now, but a phone that would do off-line navigation would be a good thing because that means one less thing to carry along.
I don't like having services forced upon me when a single download would suffice.
Haven't looked at the pro pricing or feature list, just having maps that my off-network, GPS equipped old brick can use near home is sweet enough.
If you use Android, check out OsmAnd. It uses the same OSM maps, has navigation (with voice pack too) and it's free for up to 8 countries IIRC. I have been using it for about three months and it works pretty good.
The only problem I found is that city names for some countries are in local language, so if you go to Greece for example, you would have to type in the names in Greek letters. It they fixed this, it would be perfect.
Also, the free version allows for 10 downloads, where updating a previously downloaded map (which might only be a region of a country) counts as one of them. But the paid version is only $8.