Welcome to the forum. Good luck with your hunt. I have the current 4th generation and the prior generation that my son now drives. The third generation was from 2014 to 2018. That generation had a sportier drive and the current generation is more refined. Clear benefits of both but I prefer the third generation.
Hi! I am a new Mazda owner too. Just got the 2021 3 Sedan AWD and I LOVE it!! It's really sporty and fast and visually beautiful. I also love that it has knobs. That probably sounds silly, but I'm old school. My issues with it are that the trunk opening is tiny compared to how much space is inside and maybe I'm missing something but I can't seem to lock the car with the windows cracked. Also it is keyless so it constantly searches for the key and 'reminds' in the most annoying possible way you that your battery is discharging and it happens almost immediately. That is actually my biggest issue. I don't know what the hell they were thinking. Dealer told me there's nothing they can do about it. Outside of those things it's an awesome car!!