Stainless steel line over tubing

I'm in the process of converting my 62 Wagon from a one reservoir master cyclinder to a two reservoir master cyclinder and I will be changing all the lines as well so the question is the speed shop is telling me that everyone is converting over the the stainless steel soft lines (which really look cool and the price is not that much different) and not the tubing but I would think that would cause an issue with flexing and braking coming off the master cyclinder. What do you all think and which way should I go.
Thanks