By now I have 3 of the micro rockets, I like to put these inside the seatpost. Bikeradar is not wrong though, but 20" wheels take less air so these are slightly more suitable. I have to pump several 100 strokes to get a pressure I'm happy with but with no gauge it's a guessing game. But at least these pumps get there. Due to the small size one mustn't expect floor pump performance; size matters with pumps. I will only use it when there is no alternative.
I also think the small Crank Brothers pumps are rubbish. OK for mildly inflating, but no good for getting up to pressure. I use to think much of them but since moving to higher pressure tyres I have realised they are useless. Perhaps the slightly larger ones are better, but I have fallen out of love with CBs after putting up with their crap pedals for years and not realising how much better SPDs are.