It's the second version of the PS VR. The only difference is the second one supports 4K HDR if you have a PS4 Pro and a 4K TV. In the first one if you want to play in 4K HDR you need to disconnect the VR. The second one also has built in earphones and the first one has separate earphones. Besides I'm sure you won't be using them anyways. I use my own headphones with it.
Is it worth it? That really depends from person to person. Some people get nauseous after using it for a while. For me personally it is definitely worth it. Make sure you get the 2 move controllers with it for the best experience. Game selection is great even though there aren't as many games available for VR right now.
If you have any questions just let me know as I've been using the PS VR for 2 months now.