I bought the Caiso some months ago. It was initially a little weird in my hand - a little larger and heavier than what I'm used to.
But I loved (still love) how it writes, so I persisted. Within a day of using it, the strangeness normalised, sort of disappeared, and now it is just a symphony of perfection whenever I use it. (Except for an annoying tendency for the nib to come a little loose and need to be pushed back into the section: this seems to happen only when the pen is low in ink, and I don't understand where it comes from; an air pressure issue?. Even with that, though, I really enjoy the pen, am very happy with it, and keep it inked and constantly in use).
At this price, I wouldn't buy it online. Actually, one of the main reasons I went to the London pen show last year was to try it out and (as it transpired) buy it directly and in person. I bought the flat-top version, which suits me very well.