I ran the Metz 90/90-21 on the front after the original Dunlop, and it developed a LARGE tread blister about 1/3 of the way into the actual tread life. I replaced it with the same, thinking it an oddity, and developed a large sidewall swell/blister after just a couple of hundred miles (returned it under warranty). I've heard of a couple of others having the same issues, so I went back to what my local shop had in stock at the time, which was the stock Dunlop replacement.
Gonna try the Avon Venom next since I've heard quite a few good reviews and I'm just not a fan of the stock Dunlop tread pattern or tread life.
EDIT: For the record, the Metz Marathon on the rear has been OUTSTANDING! I've got 13k miles on it so far, and still plenty of tread and stability left. I'm estimating about another 5k of life left in it, maybe a little less.
BACA Pretzel - Flyin' the highways in OK!
'08 Vulcan 1600 Nomad - "Grace"
Metallic Diablo Black/Candy Fire Red
Vance and Hines Duals
Kuryakyn Flame grips with Throttle Boss and Stiletto endcaps
Kuryakyn Longhorn offset highway pegs
Vista throttle lock
OEM light bar and luggage rack
B.A.C.A. Member, Oklahoma Chapter
Out to pasture - 2008 Vulcan 900 Custom: Redemption