I think that simile is 10km west of off-topic and accelerating away, but as with niece/brother, it's very much a matter of taste and requirements. Sure, the brother can fix your computer or go fishing with you, but I can think of some things I'd rather have the niece for...

Cutting the dodgy simile right out: there is a worrying lack of understanding here (often from very intelligent people) that things like 'practical' and 'desirable' are all relative. Lots of people who would be miserable with an N900 may well end up buying and loving the N9.