Sorry for my english...
I changed the Metzeler 880 for a set of Avon Ultra Storm II last week.
What a difference ! The bike is transformed, especially on wet pavement. I feel as confident as I was afraid with the Metz when it was raining. The bike feels lighter and really safer both on wet and dry pavement.
I only tested them during 400 miles this week-end during a trip in Champagne (France) on twisty roads, but half of the distance under hard rain and I'm very happy with them.
I can't tell how much miles they will last but I prefer change them sooner than changing the parts of the fairing, the levers, the pegs etc... with the Metzs.
I put 39 psi front and 47 rear, two with luggage.