I purchased my IQ on 1/3/12, just after it arrived at my local Toyota Dealer. I now have 3600 miles on the IQ. My previous car was a 2010 Challenger.
The IQ is very nimble and easy to see out of. The Challenger had serious blind spots. A simple lane change required lots of mirror checking and head movement.
I had the Scion Red rear stabilizer bar installed by the dealer. This part took about a week to arrived/be installed, so I had a chance to do a before/after comparison.
The stabilizer bar is worth every penny it cost IMHO. Prior to installation the rear would lean quite a bit during spirited cornering. Now the IQ maintains a flat stance in corners w/very little lean.
Gas mileage, 32-38 mpg so far. Interior, comfortable (I'm 6'2", 245 lbs) and well done. Easy to see out of the IQ. Very nimble. Parking is super easy, just pull in nose first, then back up a few feet. Turning radius is so small! Exterior is better looking than most small cars. Extra cost premium paint just sparkles!
More power, keep the CVT. The Suzuki Hayabusa motorcycle has the ~same size 4 cylinder engine, but makes twice the HP. I'm sure Toyota could produce a few more HP at a reasonable cost w/out reducing reliability or increasing emissions.
My IQ did not come with a manual for the audio/phone unit. I've figured out how to use most of the features, but not all.