It may show gains with a 60mm TB. The inner pleats of the stock boot are smaller then 60mm. Also the repetetive ridges are not good for airflow.
I could not tell any power gains personally (big surprise

), but the throttle response did get a bit crisper.
Yes it suffers from heat soak more than the rubber one does, but with some coating it's does alright. Getting rid of the stock boot alone is worth it IMO.