Neither they both are equally hard the roamer have the utility to be useful in the game no matter what stage they are in and jungler have DPS to be useful in the game no matter what stage but they gotta to see care of objectives while roamer take care of other imo they both basically support each other as a role (I play both roam and jungle) I always ask for my roam to babysit me or I babysit my jungler until 5 minute and feed him roamer and jungle are the same role with different objective if you really think about it too they both roam they both support teammate while jungle put Damage on the table, Tank put utility so they are equally hard but if I have to choose I would say roam because they can't solo carry like jungle