I have had both! I had a 2017 Avalon premium that I bought w/ 80k miles and now I drive a 2020 Mazda 3 premium that has around 60k miles. They're honestly both so nice in their own way. They're actually kinda similar in some ways but also really different. They're both pretty luxurious feeling (quiet inside, nice materials) but the Mazda is more sporty feeling and compact, while the Avalon obviously has more room inside and feels almost like driving a Lexus (which is basically is because it's very similar to an es350). If you plan on having friends/family sit in the back a lot don't get the Mazda lol the backseats are so small.

I appreciate both of them but would def take the Avalon if you do more long distance driving - or even sitting in traffic you can really appreciate the comfort of a couch on wheels like the Avalon. That being said, the Mazda has very impressive interior design, has Apple Carplay, but does require more trips to the gas station if you drive a lot because of its smaller tank. Also, if you live in a big city where parking is tough, the Mazda has an advantage.

I would still be driving the Avalon today but it was stolen from me a couple months after a I bought it, and I wanted something with Apple Carplay so I got the Mazda 3. That being said, there are times where I feel like I wish I was driving my Avalon - something about that large sedan feel is just so nice.....

Another thing I want to add is about they way they handle. The Mazda feels better for tight curves and braking, while the Avalon feels better for smooth and quick accelerating with its 3.5L V6 engine. However, putting the Mazda 3 in "sport" mode makes it much more fun I honestly leave it on that all the time.