From my personal experience - if you are looking for reliability first and foremost then buy an Avalon. I ran my 2000 for 100K miles with a total of just over $2000 in maintenance (the 90K service) and not a single repair or failure of any kind.
Only problem was....I didn't like driving it. With the steering
wheel in a comfy position it completely hid the dash speedo and gauges. The driver's seat was not comfortable when driving over a couple hours. And the suspension was too soft. One reason I bought the Rspec was to remedy those issues, and it has.
Too soon to say if the Genny will replicate the Toyota's reliability but I sure like driving it a lot more.
BTW, the German marques are known for killing you with maintenance costs but to be fair most people drive them harder as well. I was temped with the Bimmer but went with the Hyundai instead and haven't been disappointed.
The Avalon was given to my daughter who is still driving it with over 130K miles on the clock and it has had exactly one repair - a leaky gasket.