I think it would depend upon price of the Interstate fairing and how much you wanted that look.

For me, I think it would have to be a tremendously good deal or I'd be just looking for an Interstate.
I, like BF, have the Woody Batwing fairing and am very pleased with it. Great quality product, hand laid fiberglass,specifically designed with the Valkyrie in mind. Plus, with the four 5.25" speakers and amplifier I have, the stereo sounds awesome

The version with audio,does require a kit $199. that relocates the speedometer and tach to in the inside of the handlebars and slightly lowers and moves the headlight forward. This to allow the fairing to sit correctly. I've seen some other batwings installed that looked like they were too high.
I've seen some decent installations using a Harley batwing. The best of which replaced the stock Valkyrie headlight with a Harley light. The reason,IMHO,is that the Harley fairings don't quite have the right fit around the Valkyrie headlight.