¹  Navigation Information provided by the program:
    DFS - Distance From Start
    DTN - Distance to Next
    DTA - Distance to Arrival
    ETN  - Estimated Time to Next
    ETA  - Estimated Time to Arrival
    TOA - Time of Arrival
    SPE   - Speed
    HDG - Heading
    TIM - Time

²  CityMaps is also known as  Smartpath City when bundled with the Navman iPaq sleeve in Europe
    RoutePlanner is also known as  Smartpath Trip when bundled with the Navman iPaq sleeve in Europe

³  "WAV" means that it will provide a human pre-recorded voice guidance, i.e. 2 miles to next turn, 500 yards to next turn, etc...
    "TTS" (Text To Speech) means that it will spell out the next turn using a synthesized voice, i.e. In 2 miles, turn on Winchester Avenue
    - While the synthesized options appears more interesting, bear in mind that it will often sound like a "computer voice" and may be harder to
       understand than a pre-recorded human voice. I think the recorded voice is generally sufficient.

⁴  R: Road - S: Street - T: Topo - M: Marine

⁵  First rating shows my evaluation, second one as voted by this site's visitors

⁶  Map management:
   CITY - City level
   COUN - County level maps in the US (see here for number of counties per state) about 40 for California !
   CTRY - Maps by region - country, Europe  
   CUST - Custom map created on a desktop/laptop from a database on a CD/HD. Convenient but make sure you've got the right maps before you leave !  
   REG1 - Maps Loaded by region - small regions, 8/10 per state in the US and 2 per province in Europe
   REG2 - Maps Loaded by region - large regions,  2 max per state in the US and 1 per province in Europe 
   RAM - Maps loaded in RAM, improves access speed but limits area that can be downloaded at the same time. Maps are stitched for seamless transitions
   CODE - Compression/Decompression on the fly - allows loading of large maps, but can slow down display, increase CPU usage and reduce battery life
   SEAM - Maps are not loaded, they just have to be present on a memory card and any info can be accessed

⁷   /m: Maps Only        /s: Software + Maps         /b: hardware/software bundle

⁸   This is important if you intend to do long distance routing, state/state or cross country.