I was initially disapointed with the fuel economy as well, feeling lucky to get 37mpg on the first few drives, but I just took a trip through some mountains and back and was able to get 40mpg average which seems reasonable given the terrain. I was watching my driving, but also keeping up with traffic and passing trunks on some big hills when neccesary (which is really nice to be able to step on the gas - but not flooring it - and have it do something going up a hill). Additionally, last night I was able to get 53.8mpg late at night on a 7.4 mile (5.1 EV and 0.4 regen miles) in city drive (no more than 45mph). That mpg is only possible when there is nobody behind me and I think it may have been mostly charged to begin with, but I was not really trying too hard either. I think it does need some breaking in also. I have not yet compared the computed mpg to the actual since I just got the car, but on my next tank I will do that. One thing that is puzzling about the way the C-max seems to operate (and I admit to not RTFM much) is that when running in EV mode, it will drop out at the slightest accelleration sometimes, and that is when there is still about 50% heardroom on the gauge for the EV KW meter. I said sometimes because I think this has to do with the state of charge on the battery - when it is at or below half charged the EV experience is more difficult to keep consistent, but when the battery is mostly charged it seems the EV acts more predictably. Also I have noticed that sometimes when the EV is off (like on the freeway) and the battery is charged mostly, that the instantaneous mpg will go to the high 30's to low 40's, whereas at other times when the battery is being actively charged, mpg appears to be in the mid 20's - so charging seems to take a good deal of hp (or kw),and kills the mpg when it happens - one more reason to pay attention to the regen braking. These are just my preceptions from the first few drives so take them with a grain of salt.