The Zeta controllers were top notch in their day. Current controllers will generally outperform them now using higher switching frequencies and more setup options, not to mention being smaller, lighter and have LiPo cutoff available. The Zetas also do not have a built in BEC.
Another issue they may have is they use an internal battery to hold the setup info. That battery is sure to be dead by now and would need to be replaced. You would also need one of the programming moduals to set it up again.
