I got the 2015 Fit LX for its efficiency and cargo handling versatility. So far, I've been very happy with its performance in both aspects.
There is a lot of headroom in the front. I am 6' standing but sit as tall as the average 6'3" man.
There is sufficient legroom in front and rear for adults.
The steering wheel could extend a bit more, but it's acceptable.
Outward visibility is very good, which is a rarity these days.
Acceleration is good for its class, though the engine doesn't sound happy when pushed.
It handles nimbly, though not as well as my '99 Protege or my wife's Mazda P5.
The stereo speakers are OK for talk radio but are too flat and muddy for pretty much any music.
Cargo handling versatility of the rear "Magic Seats" and tall hatch opening.
Fuel efficiency (getting around 39.5mpg with mostly suburban driving).
Lots of headroom in the front seats.
Wide-opening doors for easy passenger access.
Great outward visibility plus a standard rear-view camera.
Actual knobs and buttons on the infotainment system!
Tight turning circle and compact footprint make for easy parking.
Nimble handling, but could be more sporty and provide better feedback and on-center feeling.
The front seatback and headrest push one's head forwards and forces a slouching posture. Use something like the Impreza's front seats with tilt-adjustable headrests.
Move the front grips forward.
Reduce glare off HVAC and infotainment screen (light coming from a mid-day sun glares off the CD slot chrome trim and any light from the rear window bounces off the HVAC temperature dial into my eyes).
Econ mode has too much engine braking.
Use soft-touch materials on door panel armrests and windowsills.
Move volume graphic to opposite side of screen so it's not obscured by my hand when I use the dial.
Replace the middle rear seat with an armrest with cupholders.
More length for cargo room.
Fortunately, the front headrest posts are both notched so you can flip the headrests. We also are using thin chair pads on the front seats to make up for the lack of lumbar support. Still, the front seats still are uncomfortable for stints over 30 minutes as they cut off circulation to my legs and cause lower back pain (and neck pain if you leave the headrests in their factory position). While the Fit drives fine on long drives (except for excessive bouncing over concrete pavement with all those joints) the seats are not.