Ok so as a player that has both and a leader of a group that tells my team mates that are F2P go for roshi..now 3 raikage even samui and omoi are great they really are but roshi is amazing and can be put with most of the ninjas out there..raikage is somewhat limited if u want real power for him...but mabui or samui would make a great choice for chakra for him...if you were paying in this game this wouldnt be a question cause ud get them both but if I had to choose right now...Roshi all the way, hell I even use him right now.