I have owned a 2006 Mazda 6i with manual transmission for 12 years and 244k miles. I loved that car. When car shopping last year, I knew I wanted a 3rd gen 6, I just couldn't decide on a manual vs automatic. I had driven a 2016 Sport and a 2014 Touring in manual transmission and to me they had similar feel. I felt very disconnected. I mean it was smooth, throws were fine, it just wasn't very engaging to me. Long story short, I settled on a 2017 Touring w/Premium and Bose Sunroof package in an Auto.
25k miles later, I drove a 2017.5 Touring today and can now offer better feedback on my opinion of the same year car with each transmission.
2017 Touring Auto: Transmission is light years beyond the 2008 Mazda 6 rental I drove 10 years ago. If you drive agressive with it, the transmission holds gears longer even when not in sport mode. Leaving it in sport mode will really hold the gears. I don't get the slushbox feeling, it almost feels as good as the manual I drove today. The tiptronic is meh. It auto downshifts if the rpms/speed go to low. It doesn't auto upshift in manual mode however I haven't really gone past 5k in manual mode so I can't really comment.
2017.5 Touring manual: I love the exclusivity of this. This model had the heated seats just like my car. Shifts were buttery smooth. Clutch catch point was pretty high. Clutch was super easy to push - unlike my 06 Mazda 6. I would say 90% of my shifts were perfect. The other 10% was a slight clunk. Car does not really like to be revved - similar to my auto. I guess you can but it seems like 2-3k is where you end up shifting. It tells you what optimal gear you should be in. I felt like I was shifting a lot with it - unlike my 5 speed where the gears were a little more spaced out. I was in 6th gear at 50mph similar to my Automatic. Flooring it felt slower then the automatic. I didn't care for the electric parking brake in the manual - it just doesn't "feel" right compared to a handbrake lever. Two words that describe my test drive : muted and disconnected.
Final thoughts: I have always wanted to drive the 2017.5 Touring manual - its the last year you can get with the Leatherette and heated seats with Nav in the US market. The fact that its so rare and hard to find makes it really attractive and makes me want to own it. But then I have to take a step back and see it for what it is. Its primary purpose ( at least for me) is a commuting car. Creature comforts like the LED lights with AFS, sunroof, Bose, and auto dimming mirror went from luxuries I thought I would never use to options I now wouldn't want to live without. Especially since half my commute is at night - the LED's light up the road! The manual doesn't really offer anything other then the ability to row your own gears. You sacrifice all the great features the Mazda 6 has to offer for less gas mileage, and a car that's ultimately geared for efficiency. At the end of all this, I think the best compromise is a Miata or some other weekend car in a manual and the Auto Mazda 6.
For reference, this is the car I drove:
Now if the Mazda 6 Turbo came in a manual with the GTR trim....I think that would solve most if not all my issues.