Just wanted to relate my experience with switching to the newer ME888 series tires. For many years I have run the ME880 Marathon on my '02 V92 Touring Cruiser. But Metzler seems to be discontinuing the ME880 series and replacing it with the ME888 series.
Last Fall I replaced my front tire with the ME888 tire in the stock MT90B16 72H size. The tire feels good and grips the road well. No problems at all.
A few weeks ago I needed to replace the rear tire. Problem is that the ME888 was not available in the 160/80B16 75H size. The choices were a 150/80B16 or a 170/70B16 size. Both these sizes are about the same diameter and are both slightly smaller diameter than the OEM 160/80 tire. Even though the wider 170/70 tire looks like it would have fit inside the swingarm, it would have pretty much filled that space. So I went with the slightly narrower 150/80B16 77H size.
I must say the ride is GREAT! The bike is much more responsive to lean into a turn and stay there. Traction in the turn is very solid. I know that new tires often feel like a big change since the old tire wore out slowly, but this is much more noticeable than other tire changes have been. I have well over 500 miles on them now including a couple days in the Smokey Mountains and the Blue Ridge Parkway riding 2-up with full luggage as well as commuting to work.
I'm not sure if the improvement is due to a narrower rear tire or the ME888 design but these are good tires for this bike. We will have to see how the tire life goes - time will tell.