My own preference (and, therefore, prejudice! ) is for wool. A 16 oz. medium weight wool seems fine to me whenever I've been in hot climates. And wool is wool! You'll have to pay more for wool than for PV, but it's the real deal when it comes to kilts.

On the other hand, I don't know what your plans are for being kilted. If you're into some kind of kilted activity that is likely to damage a kilt, you probably consider PV since it'll wash and it's cheaper to replace.