Depends on your group. /NIN is mostly useless nowadays with all the dangerous moves wiping or ignoring shadows. Its ok in a small group vs lessor NMs, but vs anything you'd take an alliance on it's useless for defense.

SE is dangerous, it can rapidly deplete your HP if your not careful. Being a RDM you can survive better then most other jobs except a PLD and possibly a WHM. So if anyone could ride it full time, it would be RDM.