Know a few people who have had them and most have liked them, even loved them. They are quite quirky and compromised when compared to say a UP for example - limited rear space for both luggage and passengers. The UP is only very slightly bigger but offers much more practicality. Personally, I would go Aygo, or even Yaris if you're specifically looking for Toyota or Jazz (real TARDIS) if not. All very (VERY) boring but solid choices.
I do also seem to recall that the IQ's autobox (clutchless manual?) wasn't great.