I have had the Tuscon Ultimate 1.6 petrol (same engine as the Sportage) since March and have covered nearly 3000 miles. I am averaging 28mpg in eco mode local journeys. On long journerys 0f 170 miles or more each way visiting family, I average 42-44mpg. My long term average is 32.2 mpg which personally I think is crap.
My neighbour has had a Sportage 3 trim MHEV and was one of the first to get one. They average near identical but no more mpg than I do, nor is it any quicker through the rev range.
IMHO MHEV is a gimmick to please/help company car drivers with tax and nothing more. Sadly (no rudeness implied) alot rushed to get the MHEV after the HEV was taken off the scheme, where as it would have been better to have saved the differnce in ap and gone for the ICE and putting the difference towards fuel.