Tsunade is more offensive and can be an ok chaos machine if you stack her with crits. She will also be a good investment if you slowly try to 4/5 star her. Since she will shine more when skill books come. Her low float to high float chase my be a problem for some teams. E.g. my old team had a 6 combo with mystery but if combo is initiated with standard attack it will be meh.
Kabuto is more defensive and has higher heals. Depending on how you place him on your formation, his clones can protect your team at least for one turn. 2k+ hp clones can make a difference. His chase is easy to fit in a team(at least for me, knockdown -> high float)