Expense?
Only one company makes them in any quantity and they are not cheap.
On the technical side, torriod push pull transformers don't like DC imbalance. Some folks say this is no big big deal and some insist on using servo networks to insure balance, so I don't know if this is a factor or not. One thing torroids do have is extended HF bandwidth due to very little leakage inductance. Seems to me that they may be better suited for interstage duty. Any other opinions?
Rob
