Maybe for me the easiest group is Group H and it's easy to guess which team will win the group. Barcelona, Porto, Shakhtar Donetsk, Antwerp are the teams in Group H. Of course, Barcelona have easy opponents in the group phase and I think Barcelona can go further in the Champions League this season.
Group A, G, and H are looking relatively easiest because few teams are having no enough sources to face these giants they are still capable for creating upsets and surprises which is famous in Champions League with Group C is also looking settled for the Real Madrid and Napoli because these both are superior in quality from their opponents.