I am 5'10" the back seats can be used but they are not good for long journeys, people with bad backs/necks, its cramped. The boot is ok but would struggle to get a large suitcase in one.
Cabin is a much, much nicer place to be than the Z, the magnetic suspension does make a difference but dont think my dad ever uses it as he has back pain sometimes (work related). Engine and gearbox (dual clutch) are brilliant, lovely noise, few pops and deep tone for a 4 banger. Gives you that turbo torque shove back in the seat when you floor it. Steering does not give as much feedback as the Z. Servicing aint that bad unless the gearbox goes. Standard 350z or tts, I would go for the TTS but looks wise its got enough to differentiate it from standard tt but not as much presence as the Z.