A few yrs back, a RTer had a Wizard MC or MTL OT fry on him while using a Boss TAE attenuator. There was a thread on it. He ended up getting Sweetwater to take the unit back and agree that it had failed. Boss wouldn't respond to him. He ended up sending his Wiz back to Rick for a new OT, for around 1500 at his expense. A few others had some issues, if I remember right a HiWatt, another Wizard and a few old Marshalls all lost their OT while using a Boss TAE.
I'm sure by now, Boss has fixed whatever issue the unit had. But, I'll skip it altogether and use the Fryette. I'd like to keep my Plexi OT working as it does now.