I'm really surprised by the stuff people missed in this thread. Adult Time are a 2D titan and soon after some customer surveys last year they immediately pivot to signing on VR studios. Swallowbay was literally one of the first VR studios Adult Time signed on. They already had comprehensive toy feedback for their 2D content which works immediately with their VR content - which means i think they already have like 1000 VR scripted videos thats all inclusive. But after trying it the issue is they have poor UX within VR web browsers, which is why SLR comes out on top with DeoVR support.
So yes, why SLR has 25,000 videos and the best originals around, Adult Time are moving full steam ahead, SLR's only other competitor POVR has poorer usability but they do happen to have around 1000 videos from Virtual Taboo and if you're a virtual taboo fan POVR can sometimes feel worth it instead of just having a Virtual Taboo subscription. Honestly if SLR could get Virtual Taboo it would be a killer blow imo, Virtual Taboo have 3 updates a week and despite not even being interested in the fetish myself, the casting quality is superb.
Anyway, that's my take as a fan - Adult Time is a new player that's aggressive and POVR's only value is Virtual Taboo imo