I had run 70k+ miles on my Michelin Energy MXV4+s in 195/65/15's and really liked them. I wanted to go to a larger diameter tire 205/70-or-75/15. I put a set of 205/75/15's on and drove them for a little while (10 miles or so). They cleared everything but it was a close fit and they looked out of place and drove poorly.
So I tried a set of Yokohama Avid Touring 205/70/15's
They rode/drove nice, I liked the RPM reduction (~6%), it made my speedometer ~accurate (half a needle width slow). My initial reaction was that they didn't roll as nicely/smoothly/etc. After driving them more and more on my same daily route I just wasn't able to coast the same distance at the same speeds that I was able to with my Michelins. I drove them for ~10k miles and one of them broke a belt.
I replaced both front ones with General Altimax RT's also in 205/70/15's. I noticed a difference in rolling resistance right away. After a couple thousand miles I also replaced the back ones with the same thing. I don't have any hard data but they definately roll at least as well as the Michelins. I can coast approximately the same distance as I could before at the same speeds.
For any normal driving the taller tire is nice. Combined with the 0.681 5th gear it's about 30 RPM/MPH so 1800RPM @ 60MPH, 2100RPM @ 70MPH, etc. If you do any trailer pulling you'll definately notice the lower RPM's as you are definately on the negative side of the torque curve. It will still pull it, but it works much harder and the cruise control really works to maintain speed with the trailer on rolling hills.
We'll see how the General's wear - they've been good so far for MPG's (mid 50's with no effort).
Hope this helps someone make a decision.