An Avalon is a class above an Accord since it is larger and more luxurious. They don't sell many which is why they're hard to find.
Why aren't you comparing the Camry V6 vs. Accord 2.0T? Those are direct competitors. A Camry XSE V6 is the sporty version, XLE V6 is the more comfort oriented one.
And yes, the Toyota 3.5L V6 is bulletproof and proven, whereas the 2.0T in the Honda is unknown.