OK, I have SWK acrylic and heavyweight wool and a USAK Semitrad. For my money, I will not buy another SWK acrylic. They are OK for knocking around but just do not have the same feel as a wool or PV. My SWK Heavyweight is one of the rare MacRae Ancient Hunting. I'm seriously considering taking it apart, adding steeking, cutting out the excess fabric at the back and putting a stabilizer and hair canvas in to make it fit and hang better.
My USAK semi-trad is in Marton Mills wool, not PV. This is my #2 go to kilt for semi-formal and casual wear. Rocky makes a great kilt.

I would suspect your decision might come down to cost. If you can afford it, go for the USAK, if not go for the SWK heavyweight wool.

Brian