It really comes down to how much info you want to watch. 99% run a single wideband with no real issue. I suppose it would be good to watch for injector issues bank to bank.
I currently run dual widebands, but that's because I have the stand alone and it can adjust bank to bank. If I was still on the stock ECU I'd probably still be running the single PLX I had forever. It never gave me issues.
What wideband are you running now?
PLX?
Does PLX offer a dual wideband kit?