So, you think because you did not have problems with your Avalon, then they are all problem free? Think again. Try this and see what you have to say then. Do a google.com internet search using the words "Toyota engine sludge", and discover there are people with worse problems than this guy even. All cars are not perfect, including Toyota, believe it or not.
The Avalon is known to have noisy brakes, even when they are in good condition. No mechanic should have charged you to replace new brakes, and if you paid for them it's your own fault. I own an Avalon and had no brake service until 70,000 miles.
There is no need to trash a car brand. More because of the fact not every one places the right oil in cars. Not every person uses the right brake pads. And how do you know the man working on your car is not dodgy? Not every car is perfect. But the amount of problem cars to good ones is more 30-70%.
It is not the car's fault that your mechanic installed bad brakes on it. Everyone should know that consumables such as brakes, tires, oil, filters, belts, and so on have almost nothing to do with car design. The only thing that may be "wrong" is the specification for the brakes - perhaps too small pads or discs... but even that can be easily remedied by installing parts of superior quality.
As an example, I always use Brembo brakes and Michelin tires, regardless of the car I drive.