I went through this years ago with the Nissan Versa at its original launch. It was projected to be one of the most reliable subcompacts at the time.
14 repair trips to the dealership for 26 individual problems in 26k miles... I have no idea why I put up with that car so long. I wasn't the only one, either. The much-vaunted CVT transmission fell WAY short of EPA estimates (while the 6-speed manuals, which I had, were mostly dead on) plus a bunch started wearing out after 80k miles or so. TPMS issues, BCM issues, electrical issues, you name it. Even the manual transmissions weren't free from flaws... it was a cable shift system, and sometimes the shifter would grab the cables for 2 gears and jam up the transmission. It's pretty sad when the most reliable part of a car is the radio. Granted, Nissan has worked out the (pretty freaking severe) teething issues after the first couple years, but it just serves as a cautionary tale as to what projections mean for brand new models: precisely nothing.
From what I know of recent GM subcompacts (which, I will grant you, isn't a lot) is that, at least up until the Sonic, they've been boring and uninspired, but not particularly unreliable.
But the Sonic earned a "better than average" on True Delta's reliability survey for the 2012 year, which is impressive for a first-year model. Their projected reliability at numerous other reputable sources was also projected to be very good. I like the styling, LOVE the interior, and for the money, only a Kia could beat it for features (though not in design).
So yeah, the original title of this thread is quite misleading. But I'm very interested to see how, in the end, it stacks up against ALL competitors in the segment.