My idea of a good vehicle is one you can harmonize with. The Yaris does a pretty good job of that for me providing close to ideal basic transportation. Gets you there fast and does it comfortably at a respectable fuel consumption rate. My biggest disappointment has been no place to hang a couple of clean shirts and pair of slacks. A fairly easy problem to fix but a real annoyance the dealership should have made sure was looked after. Seat belts work better than most cars but you need to make sure they are in place before you begin moving. I've had mine for 6 months and have 23,000 kilometers on it. Nothing has broken and no rattles.
It is difficult to keep under the posted speed limit because it is so zippy and responsive at both the throttle and the steering.
Another top end gear in the manual gearbox would be nice. Some additional soundproofing would help reduce some of the road and engine noise so prevelant in the 60 MPH plus range. Another inch of leg room would be a real asset to us tall people. Could gain that on seat height adjustment.