The only real downside to owning an Up, is that its not as powerful or fast as mainstream family cars.
Its a Citycar, but if your prepared to do very long journey's in it, it will easily cruise at the safe legal limit on the motorway, and eat up the miles if asked to do so,
The Vw Up can achieve anything its asked to do, but you have to drive within the cars capabilities, and realise a longer journey may take longer in a small car, than a larger one.
The furthest ive driven in a car of similar size to the Up, was in my mothers Vw Lupo.
I drove close on 480 miles on a round trip, in one long day, the car managed it with ease, and did it on less than a full tank of fuel.