This car is selling well to both retail and fleet customers. I'm in a 2011 Sonata rental as well and have put a few thousand kms on it. Oddly, it has equipment somewhere between GL and GLS... based on what I've seen it's a GLS minus the fog lights, sunroof, and leather wrapped wheel. Am thankful for the freebie XM radio preview.
Have to say I quite like the thing and could live with it.
Steering feel is the biggest negative in my book. It's not bad, but not good - you get used to it. After sampling a few rentals (Civic, Outlander, Sonata) I didn't realize how much steering feel differed in vehicles, and how good my car was/is (IMO). The recent steering recall further reinforced my concern. And sometimes the suspension sounds hollow over bumps, especially at low speeds. Also find the trip computer logic is not as user friendly or thoughtful as the VW (have to reset each value individually - time, fuel economy, etc whereas VW resets trip 1 and stores trip 2 info automatically), but they're well on their way. Interior materials aren't the greatest but perfectly acceptable, their fit is good, and the design is pleasant.
Otherwise I think the car is great. Very classy design, roomy and comfy, great equipment (bluetooth, heated seats, steering wheel controls, etc), powerful, reasonably fuel efficient, and value priced. I like the suspension's ride/handling balance, but think the tires must be cruddy because when the road turns wet cornering abilities are low - or the tires were abused by the previous renter, but think they're just geared toward fuel efficiency.
Speaking of fuel economy, on my 240km commute I'm netting between 6.3-6.9L/100K (typically 6.7) and get around 940K per 70L tank. This compares to my Golf Wagon which gets 4.5-5.2L/100K (typically 4.9) and closer to 1100k per 55L tank. Short trips and city driving are far less efficient than the diesel, but the difference in highway driving narrows - especially around 90km/h. Still, not half bad for the size of the car.
I've had a lot of positive experience with Hyundais and would recommend the car.