One very good source of information on Japanese trends and products is Nikkei Trendy (Japanese). This week there is a survey on canned coffee use and preferences. For those interested in this topic for professional reasons, the entire survey is available for sale. For those who simply have an interest in trends, the on-line version should be quite sufficient.
I will just mention a few points I find interesting.
1) preference: sugar free/black > latte-type > low sugar/milk added > sugar/milk added > low sugar/black > no sugar/milk > expresso > sugar/black,
2) the biggest deviation in the above is with latte-type drinks (including cafe au lait) which are much more popular among younger people than older people,
3) canned coffee is much more popular than chilled cup coffee, only among women does the preference come close to that of canned coffee,
4) reason for drinking canned coffee: change mood or feeling > relax > wake up > no reason > need for something in mouth > to concentrate,
5) people who smoke or frequent convenience stores have the strongest preference for canned coffee,
6) ability to mention a brand name: Boss > Georgia >>>> Wonda > Fire > others
The interest in low sugar products is clear, as is the excellent marketing job Suntory has done with the Boss brand.