Having researched all available options, this is the one that seems to suit most circumstances best. It's robust (not a whiff of any malfunction, bugs or instability), flexible (adapts to most situations - well), fully-featured (uses Google s/w and maps, loggers and logs) and very easy to use.

HoudahGeo has a simple and straightforward interface, works well with peripherals (eg a logger) and integrates perfectly with Aperture (2), for example.

It's very reasonably priced, technical support is outstanding (the developer goes to infinite lengths to answer questions and recommend solutions with great speed) and the overall look and feel of the s/w makes what could be a bit of a chore something you end up wanting to do.