I have/had a sub to all of these sites and they have mostly been collecting dust since SLR did AI PT to their entire catalog. Non PT feels like a step down to me. Having said that, if PT isn't a big deal to you, I think POVR is the second best value to SLR, but you will need to (should) install Heresphere to steeam, which is the only player besides DeoVR that is worth a damn. You have to pay for Heresphere, but it is worth the money. Heresphere works on POVR, VirtualTaboo, and Czech (maybe Badoink, but they pissed me off so I stopped using them).
Heresphere is good at AR passthrough too, and I currently mostly wander from SLR/DeoVR these days only to watch ARPorn channel on VRPorn.
Heresphere offers an overwhelming amount of adjustability that their pretentious fanboy base loves, but I can navigate the basics well enough with the help of a Google search here and there.
VRBangers and VRPorn use the Playa App which is such a pile of junk I don't even visit the sites anymore. You can access VRPorn via Heresphere but if you like to watch snippets of scenes like I do it quickly cuts you off as it treats Heresphere streaming like you are downloading, and they have a DL cap.
VRBangers makes great scenes but they also stopped the ability to download their movies other than using Playa from your desktop. And getting Playa on my Windows laptop required me to install and register with Steam. It seems like VRB likes to make things difficult.