I Have been in the normal mode for the last tank just to see the difference between the eco mode and normal. On normal I got 46.o for 382 miles. In the echo mode I had a 50.5 average for 645 miles. the last for overall on 1027 miles it was 48.9. this was mostly city but some country drives and no interstate. Have just Filled up with non ethanol fuel to see if there is a differance. Only 10cents difference sowill go back to echo mode. Still have not recieved e mail from prius chat shop on questions i had on accessories.
I've had my 2011 Prius4 for about two weeks. I am averaging 48MPG mostly highway miles. Its been cold so they say your MPG will be lower. Hopefully it will go up in the coming months.