Mazda3 vs Mazda6 how to decide?

You really can't go wrong with any of the cars you mention; all three are great cars, but there are significant differences.

Both Mazda 3 & Mazda 6 are fun to drive cars with excellent overall reputations. The M6 is a sleeper and has not sold well in the US so it will be harder to find. But, thanks to its sleep status, will probably cost less than similary equipped M3. A quick search for model years 2014 through 2016 in Seattle area shows 10 M6s priced under $13K vs 26 M3s. So the selection of M3 is significantly better.

Aside from price, I'd say it boils down to your size and comfort preferences. The M6 being is larger and will be more comfy. The M3, being smaller, will be more sporty but a bit rougher in the comfort category.

The Honda Accord is perannually a well made favorite of many and a notch better overall than a Mazda. It will be larger and more refined that either Mazda and due to its popularity, will cost more. To get a similarly equipped and priced Accord vs a M6 you would probably have get a year older, higher mileage Accord.

We always appreciate hearing what you end up with and why. Happy car hunting!

The 2018+ Accord is more highly rated than the Mazda6 because sportiness and steering feel aren't important to most buyers. The Accord is the better car for people who aren't swayed by the styling and feel of the Mazda6. The Mazda is more cramped and less practical than the Accord due to the styling of the Mazda. Also, the ride and road noise is a little more pronounced in the Mazda. The interior technology is also not as modern as the Accord's.

One thing I forgot to mention is that I LOVE the seat comfort of the leather seats in the current gen Civic and Accord. Mazda's are ok (not great), but I think Honda wins in seat comfort. I actually think Mazda's fabric seats are more cushy and comfortable than the leather ones.

For the Mazda3, there wasn't much of a different between 2015 and 2016 at all. So, go for a 2015 if you want and it won't make much of a difference compared to 2016. 2017 was a slight refresh that had a softer ride and less road noise, the addition of an electric parking brake, new steering wheel and higher-res infotainment screen, etc. Some of the Mazda3s are made in Mexico (I think only 2017+ some were from Mexico) and some are from Japan. If the VIN starts with "J", then it is Japanese-made and starting with "3" is Mexican-made. People say the Mexican ones are of lower quality, but I doubt it. I haven't seen any trend proving this. A lot of cars are made in Mexico and it isn't a huge deal.