750 V-Twin? No idea.
Generally speaking? I've run them in past cars and my current car. OEM/recommended by Mitsubishi. I get 60K out of them, usually. Coppers are cheaper but have to be replaced more often. Have had them in a few inline 4 (I4), and a V6 too.
If you do low mileage per year, or turn the wrench yourself, coppers are fine; you'll pay more in the long run (labor) for coppers if you're paying to have them swapped out more often. Iridiums, as far as I know, just last longer. They come in the same heat ranges, you can gap them as needed, etc.
Might burn cleaner or spark better, but if your engine is mechanically sound anyway, the differences would probably be minimal at best. If the bike came from the factory with standard coppers, it won't hurt it to keep using them.