No, not a subscriber to any of these. I have my own VXX/XIV trading model which is a blend of two of the strategies that volatilitymadesimple writes about. They are all based on the same 2 principles (or a blend of them) they either look at whether the VIX future curve is in contango or not and whether realised vol is above or below implied (VIX or VIX future) there are various methods and all work better or worse depending on market conditions. The other factor is how quickly the strategies get you out of short vol into long vol positions. If they are quick they suffer from many wrong signals but if a massive move comes like we had recently they save you most of the loss and make a ton of money by being long early. So there is a trade off and you have to find a happy medium.
All of these strategies are quite risky and suffer big drawdowns do be careful with allocation. They also all made fantastic returns historically but I have a feeling that the golden period of the last 5 years is coming to an end and we'll see more volatility again and a less steep contango so it will be harder to get to the returns of the past. Also this is a very popular and therefore crowded trade which leads to big risk off crashes where volatility explodes. The big jump in VIX we had in the recent sell off which was just a 10% correction (albeit a very fast one) is attributed by some to the rise in volume in these VIX ETPs.