A large part of the evaluation of a piece of software (or anything for that matter) has to be its price, and something that would be bad in an expensive piece of software is less of an issue in a cheap or free application.

It doesn't stop something that is bad being bad, but it does excuse or mitigate certain things.

I used mapper going across the states on holiday last year, as well as navman on my old pocketPC. Mapper certainly has UI problems getting maps, but for the price it seemed very good.