I had recently turned in a lease on a Honda Civic. Reading the great reviews on the 2008 Yaris, I picked that car after a brief test drive. For one, the interior of the Yaris is incredibly different than the Civic; there are far less controls and more space. The size of the steering wheel was even surprisingly smaller!
The first thing to get used to is the dashboard. The dashboard's simple instruments - RPMs, MPH/KPH, digital fuel reader, digital odometer - are all central on the dash, not right above where the driver is. This is a big difference to anyone who is used to looking straight up and seeing the dashboard settings right in front of them. Also, the digital fuel reader only shows a total of 8 bars - it's not detailed to know how much gas is left in the tank. (That, combined with not offering an option to show the mileage left before a refuel makes knowing when to refuel leave a little guesswork.) Also, the dash is leaving out the engine temperature - something that, with the Civic, I relied on even if I knew that the engine wouldn't overheat.
The engine itself is a tiny thing - 4 cylinder. As the car had only 30 miles on it when I got it, it took a little effort at first to have it reach 80 MPH, but it drove comfortably at that speed. The handling of the car is a little tough in winds - I was having trouble keeping the car steady in 15 MPH winds on a flat terrain.
However, on positives, the car is incredibly roomy - I was able to fit five people in with plenty of room. The trunk itself is large and spacious, perhaps a little larger than my previous Civic. The gas mileage is also comparable - I'm able to get around 400 miles on a single tank (mostly highway miles). The car is also quiet, as long as the terrain is quiet and smooth - with having such small wheels, it's incredibly bumpy.
In conclusion, the Yaris is a decent car; it's get you around town, but it takes some getting used to if you're switching from another brand.