Fan updates do not count as alternatives IMHO. The person 'updating' it usually does not have a grasp of the entire codebase and is just fixing errors as they popup without really knowing what they are doing.
may be true in general, but that would disregard all projects with more than one maintainer and / or ppl joined later
about alpha map and mapnotes: it seems to be rewritten from scratch kinda and have been maintanied by the same person quite a while. Just still the 'fan update' in the name. Both r running fine and are TRUE alternatives mho.
If your looking for replacements, then Mapster + HandyNotes (& Assorted Modules) + TomTom gives just about a complete replacement of all that Cart2 had / has to offer.
Cart3 however is more like google maps, it's something you'd use instead of mapster.
Dont forget Alpha map (fan update) and Mapnotes (fan update)
Both are under active developement and serve very well.
Mapster and handynotes are NOT the only option.
Another Option could be Metamap (someone released a current wotlk version, dunno if he continues though)
Esp. since handynotes has NO Importmodule (as far as i know, correct me if im wrong pls!) for cartographer and or metamap i really dont like to use it. TBH its a killer argument for any new notes addon that come w/o an importfunction/module.