I think the difference comes in the fact that the PX8 are more premium than all the other headphones on your list with the exception being the H95. The HP70, and I'm assuming you mean the NAD Viso HP70, is one of my all time favorites when it comes to wireless anc sound quality for the price. It's just very outdated at this point and can't compete with the likes of the PX8 and H95 when it comes to features.
I put the PX8 in the same category as the H95 when it comes to sound quality. It's sound is what I consider a more unique sound to the H95. Both are a tier below the Bathys and 5909 in sound to my ears, but better as an overall package. When compared to the H95, the PX8 is not as technically accurate. The tonality will be a matter of preference. Both have bass emphasis, just in different ranges. The PX8 has more emphasis in the mid to high bass frequencies. The H95 has more emphasis in the deep, sub bass frequencies. Overall, the bass is a little cleaner and more linear on the H95. The mids are more front and center on the PX8. Produces vocals better. There's more musicality in this range on the PX8. When it comes to treble neither are treble monsters, but the H95 has a little more extension and detail in this range. The PX8's treble is a little more relaxed and uneven. One thing you will notice immediately is that the PX8 goes louder than the H95.
I personally have no issues wearing the H95 out and about in public and actually use both the H95 and PX8 out and about quite often. Which I grab depends on what I'm wearing LOL.