Got a 1995 M600 and it does suffer carb iceing when certain weather conditions (damp and a fairly narrow range of cold around 0C) - freezing fog is the worst. Petrol additives help, but not a total cure. Ducati also did a carb heater kit which uses hot oil from engine to warm the carbs and stop them icing. These were fitted as a free mod to some bikes (though it is not a formal recall) in the early days. I've had the bike from new but never got the kit fitted at the time as they ran out of kits and I moved away from the dealer I'd bought it from so never followed up. But few years ago after a really bad bout of carb iceing I wrote a couple of letters to Ducati UK who after a bit of persausion gave me a kit for free (though I had to pay to have it fitted). It works pretty well for winter and there is a valve so you can turn it off for the rest of the year....
So don't be put off the M600, it is a good bike and the carb issues can be sorted and anyway are only a problem with certain specific weather conditions at limited times of the year (and I find revving the nuts off it helps too
)