I have about 300 miles on my 6 speed and I drive mostly all city. I have been focusing on steady driving and getting into higher gears as soon as possible. My display says 34.8. I am working hard on the driving style to get this
With my 6 speed I'm on my third tank and have been getting 28 mpg in city/stop and go with the AC cranked 90% of the time. I've been more worried about breaking in the motor right than mileage, so I've been varying the RPMs, not letting it cruise at a steady RPM.
I now have a little over 4k on my 6speed and I average about 29mpg with mixed driving. When only City I get about 28mpg and Hwy only I get about 34mpg. Currently taking a new average after installing my new Cold Air Intake, so we will se what we get from that.
One second tank, ~480 miles, 90% city driving, 28.6 MPG on the computer. Manual calculation for first tank was 27.6 MPG (lower due to dealer/initial delivered fuel). I was going to be very happy with 26-28 MPG, but I expect to see 29-30 in the city once everything breaks in. The six speed is a little notchy and 3rd and 4th can be hard to find if you are skip-shifting or down-shifting from 6th to 4th. It's hard to really give a fair assessement of the manual since my weekend, runabout is a 91 Mazda Miata 5 speed manual, probably one of the best manuals available. (okay, the Honda S2000 is pretty slick) What do you really expect from a crazy linkage setup.
The think that really surprised me with the cube are the following. Plenty of power if you need it, very quiet even on the hwy, steering is very quick but with the electronic variable assist rock solid on the hwy. I am a former Infiniti Q45 owner, so I know quiet interiors (mmm, whisper quiet).
I made a 90 mile run on the local autobahn (GA 400) and she was clocking 36 mpg! Can't wait for the first real hwy trip.
I don't think you will go wrong either way, very impressed.