Features are extremely lacking. Basically, it's points are GPS locator, street map, and Interest mapper. However, the ability to use templates, overlays, waypoints, custom databases, partial maps, custom labeling, etc. (stuff that used to be in StreetAtlas and are now incorporated into Google's system) are completely missing. Almost all functionality is directed to very clumsy buttons and a few key equivalents. Most of these functions are not present in the menubar, and therefore most automation functioning is not possible -- and if there are alternatives, they aren't mentioned.
It's easy to understand and use, but then again there are no significant functions to confuse you.
Stability is fairly good, I only had it crash out a few times when using it to confirm positioning for a major NYC location pamphlet for a convention. It always restarted cleanly.
However, it has two two drawbacks (three considering the fact that it is now late 2006). It is extremely slow and clunky (and could use a major interface remake) -- StreetAtlas PC works Significantly faster under Virtual PC (at least 3-5x).
It's freakin' huge! Rather staggeringly so. Make me wonder what database form they used for all the information, and whether it would work faster without all the points of interest (or at least major parts of it).
And now that it's late 2006, the company hasn't done anything with the database (streets or POI) in 3 years... and from their website, doesn't look like they will anytime soon.
If they had supported templates and overlays, they could have been a major 3rd-party supported software -- Anybody notice how many people are plugging into Google's map system with extras, like subway maps, timetables, and the like?