'10 Sport+Touring, daily driver, 42,000 miles give or take.
Still looks new (thanks to careless driver who backed into me recently, so I got a new front bumper and respray the front end for free!). Only minor wear on driver's seat bolsters. No creaks, no rattles. Interior still looks 100% new aside from driver's seat and plastic scuff plate (and plastic driver's door trim where I scuff it with my shoe from time to time). Passenger area is mint, as I rarely take passengers. Most non-car people hate the tiny interior space, girls hate the road noise
18-18.5MPH average in SoCal traffic and lots of city streets. I see 22-23MPG on the rare occasions where I do a lot of freeway miles on a tank.
I've had the gas gauge issue (fuel sender unit, actually), and the steering lock issue which resulted in a tow to the dealer.
Otherwise, factory recommended service, still using Nissan ester oil, all service done at the dealer, no other issues to report.
I use OEM tires still, on my third set of rears IIRC, second set of fronts? I can't remember. Tires are expensive and don't last long, but they grip like hell and it's a sports car so I can't complain. Expensive service and tires are part of the game.
Gripes about the car? Rearward visibility, road noise on the freeway, lack of interior space. Of course I knew about these things going in, but after daily driving a 370Z since November of 2010, I think my next daily driver will be a bit bigger. The interior space is my only source of frustration. Not the lack of seats, rather the lack of storage space. I'd love to be able to hang a suit jacket, or toss my golf bag in a car without removing the woods first, or do some shopping without wondering if something will fit in the hatch (and using the passenger seat as extra storage space pretty often).
Most days though, it's perfect. I'd say out of a 30-day month, there are maybe 5 days I really wish I had more space due to wanting to carry stuff more easily, and another 5 days where I sit in a lot of traffic and think "this would be more bearable with more leg room".
I never think "I gotta get an auto" or "I need 4 seats". The lack of visibility is an annoyance backing out of parking spots or merging/changing lanes, but so far it hasn't caused any real issues.
What else can I say? My gripes come from daily driving a sports car. You're going to sacrifice with any sports car when it comes to daily driving. The noise and stiffness don't really bother me much. The car is well built, reliable, and fun. After a good wash/detail, 4 years into ownership, I still find myself turning back to look at the thing as I walk away. I still smile when I drive it.
Here is the ultimate question - would I buy another one? Hrm. Well, what is new on the market that is a better option? The new Mustang GT is probably a great car. I considered a Mustang before buying the Z, but Japanese reliability won out for me. Maybe a new STI, but the last STI was a great powertrain surrounded by a boring body and awful interior. That hasn't changed much. Other than the 2015 Mustang GT, I can't think of a better sports coupe in this price range. Even then, I don't know if a Mustang would feel as solid at 40k miles as my Z, and that's really important to me. I like quality and reliability more than outright power and speed. I never drive my Z and think "only having 330HP sucks". It's plenty of power, almost all of the time.
I have shopped various sedans from the IS350F to the new Acura TLX and a Q50S, but if I had to buy a new 2-door tomorrow, 2015 Mustang GT consideration aside, I think I could be happy driving a Z for another several years.
I was really hoping that Nissan would release a new Z before I wanted a new car, but that likely won't happen. I'm guessing that I'll keep the Z one more year and then get something new.