To avoid the popup, go directly to http://chotto.free.fr/tatami/Metro/ .

I have used the PalmOS version for a number of years. It is reasonably good if you already know the names of the stations you are starting from and getting to. Browsing by landmark is available for a few cities but don't depend on it exclusively-- for instance, ask for service to "LaGuardia Airport" and it will tell you to get off at Roosevelt Ave. and take the shuttle-- there isn't a shuttle, of course. You can take the Q33 bus but that crucial route number is for whatever reason omitted.

The algorithms it uses to calculate transfers are quirkly. Partly this is because they are time-agnostic in some cities, and partly because conditions on the ground will outweigh even the best guide. But here's a baffling quirk. If I am coming down the 6th Ave Subway trying to get to New Jersey, it will invariably tell me to get off at the 4th Street stop and walk to the 9th Street PATH station. Why? Both the subway and the PATH have stations at 14th Street, in fact directly adjacent to each other, so there's no reason not to do the transfer there. Especially when Christopher Street is overcrowded and the masses spill up to 9th.

All that said, Métro is a fine program. The Palm version is very intuitive and well-designed. They've been quite sufficient to get me around in London and unfamiliar North American cities, and it's a lot easier to carry around a set of "good" directions for dozens of cities than "expert" local residents from dozens of cities. Especially for free.