The Sonata is doing fine but I only have 600 km on it. General level of comfort, NVH, roominess and performance is way ahead of my Corolla, that's for sure.
The Corolla is a perfectly good compact car but my mistake when choosing the '05 3 years ago was going down from a Honda Accord, a car that I really liked.
First of all, everyboydy knows that the Gen 9's driving position is awkward. I had to have my feet too close (especially with winter boots on) in order to have the steering wheel still too far away and the seatback too upright for comfort. I trimmed my dead pedal which helped but the lack of a telescoping wheel made getting the right driving position impossible. My Sonata desn't have the telescoping wheel but the seat-wheel-pedals relationship is good from the outset.
Listening to the radio or CD on the highway was next to impossible. Too much road noise coming from the floorpan, fenderwells and firewall I guess. I put better 3 way speakers in the doors and saw no change. On bad pavement and concrete highways and worst of all, in rainy weather, it was painful. It's a car that made you drive at slower speeds on the highway.
The suspension was a bit jiggly on bad city streets, read everywhere in my area. Things were better with 195/65-15 Yokohama TRZ's I put on it but not the best.
The car got tossed around quite a bit in windy conditions on the highway. Light, narrow and tall cars can't defy the laws of physics no matter what. But as a city car, it was great.
The interior was well laid out but contained too much hard plastic causing various intermittent rattles. Heating/ventilation controls were of the ancient cable operated variety and felt cheap. Too bad because the platform felt very stiff.
Engine management and electronic throttle (DBW) were less than perfect. I had the no-start condition once in a while after being stopped for a couple hours and also began to experience the hunting fast idle last winter in the -12 to -15C range. The fast idle was too fast (up to 2000 RPM) and throttle just off idle was jerky when cold. Also, the engine RPM was always racing up on a fast 3-4 and 4-5 upshift. Like the electronic throttle was behind the curve for a fraction of a second on those occasions and made me feel I was shifting like an amateur, though I drove manual transmissions all my life and never experienced this behavior in any other car.
Gearing of the 5 speed was also less than perfect. 4th was too tall and close to 5th which left a big hole between 3rd and 4th and killed acceleration in 4th.
The Corolla would last for ever but was lacking in general refinement and details surprising coming from a company like Toyota. I would have kept it maybe 3 more years (like I usually do) but the 4K discount on an '08 Sonata was one I couldn't resist. Cash deal mind you and fully paid for so it's not like I did a dumb thing to refinance a car that was not actually fully paid for before re-embarking on another loan or something.
Toyota is taking a big chance by delaying the 10th gen one more year, so let's hope it meets and exceeds all expectations so it can go chasing Civics, 3's, Lancers, Sentras, etc. and have a chance of winning the war instead of relying on the Toyota name and typical Toyota reliability and resale value to enrole new customers. On that subject, I had an e-mail conversation last week with a lady I know (low 50's) who's been driving Hondas for 20 years and she just traded her '04 Corolla for an '07 Elantra. Things are not static and do actually change in the auto-industry with newcomers Hyundai/Kia starting to attract old time Honda and Toyota repeat buyers. I also being one of them.