15" speakers - JBL k140vs EV SRO

[Lizard King]

I play guitar through a 2x15 cab ( an old Crate cab).  I loaded it with JBL k140s and it sounds great.  My favorite "junky" music store has a "home made" Bassman 2x15 cabinet loaded with SRO's. Before I spend the money to find out for myself, does anyone have an opinion on these two vintage speakers?  I could get the cab for the cost of the SROs so I'll probably just get it...but you know what that leads to: a second 1965 Bassman head....Ahhhhhhhhhhhh

(I don't think you can send SROs back for free reckoning anymore, but a friend of mine was still getting his reckoned 30 years after the fact)