Hi! I personally feel Roshi is a little better especially for the long term as it has a lot of potential and damage as a tank. However, the best thing I would recommend is saving 300 seals and taking advantage of one of the seal rebate events and get the rebate as well, which will in essence give you a high chance of recruiting both Roshi and Han =]

Always take advantage of rebates and maximize your potential for rewards!

~Jib