The car has been utterly reliable. The only time I've been back to the dealer is to get the first service.
First service (10000 miles) was done while I waited (took around 40 minutes), and cost £80. Dealer service in general is streets ahead of that I received with my previous car (a Seat). I get the impression that Toyota keep a close eye on their dealers.
The car is quite quick when revved hard, though not much torque so you often need to change down a gear or two to get decent performance.
Economy is excellent - I get around 45-48 mpg.
Build quality is very good - no rattles or squeaks.
Sound quality from the CD player & speakers is very poor. Very 'tinny'.
Ride quality is very poor. Car seems to bounce around a lot on the road unless the surface is perfectly flat.
In general I don't find the car particularly comfortable - my back gets quite sore. This is partly my dodgy back, but I think the poor ride quality doesn't help.
Car is roomy inside, both front and back. However the boot is tiny.
I quite like the electronic dash display. I don't find it distracting (like some of the magazine reviews say).
Overall quite pleased with the car. It's reliable, cheap to run, and hopefully will hold its value quite well. Just a shame about the ride quality and the CD player.
I probably won't buy another Yaris because of the ride quality, but if that's not a big issue for you then I highly recommend it.