Hi OP,
Panamax and Furman are owned by the same company, and while some features have transferred some have not, and the mix of features per model is maddeningly complicated.
Key features for noise reduction are LiFT and the other is SMP. Lift is linear filtering and SMP is series mode surge protection. The latter also happens to work much better for noise reduction due to a variety of technical issues. Panamax still lists Linear Filtering as a key compnent of some of their models.
Another feature I am fond of is voltage regulation. Panamax and Furman both have some models with this features. I believe, but am not 100% sure that the better value among these features is either this one (15A) or this one (20A) but they lack some consumer features like switched outlets.
I _think_ Panamax at one point had a series mode protection model but if so I can no longer find it.
For noise and surge related issues I don't plug any equipment into the wall without them. Warranty's be damned, I'd rather prevent a surge than file a claim.