I'd like to clarify my comments..... I brought up the Roadsmart front (especially the French one) because of the alarming number of very serious failures with huge bulges and chunks out of the tread. To my knowledge, no one has crashed yet, but they have the potential..... Dunlop has been made aware and to date have not issued any response... I absolutely would not put a Roadsmart front on anything. As for the rears, I know of no failures, and I believe it is a different (dual compound) tire, perhaps made elsewhere, and may very well be a great tire... just hard for me to put any confidence in Dunlop. As for their former tires, they were known for their harder compounds and long life, and IMHO, great if you're not needing a sticky tire for canyon carving. If you're a milder rider, they're fine. Dunlops in general will not fit my style or needs.
As for Metzelers, the cruiser guys and the Goldwing guys have mixed comments about the ME880's (and Dunlop Elite 3's), some like that they last longer, while others complain they are a bit slippery in the wet after they wear 25%. I had a Goldwing with them, and can attest. They are more of a cruiser tire. It is more likely the HD guys comments are in part due to no ABS brakes, rear wheel lockups, and perhaps slippy in the wet.... lots of reasons they might have comments about not liking them. Yes, I shake my head when I hear comments that clearly show that a bike rider knows nothing about tires.... low pressure for comfort, indeedy!!
I'm not a tire expert, but I do look for comments, hoping to separate the wheat from the chaff and make intelligent decisions on what is right for me, and what to try for my own experience. So, please do keep the comments coming, and this old dawg will try to keep on learnin'..... but I also will pass along my experiences and as factually as I can report what other sport tourer groups are finding.