I got my Vive about a month ago and I just got my Rift on Monday. I was fully expecting to prefer the Vive. I have been absolutely loving the Vive and I am amazed by everything it has to offer. The motion controllers are amazing and the roomscale experience is very, very fun. The games are hit or miss but there are enough interesting games that have kept me very happy with the purchase. It is a ton of fun and I do not regret the purchase at all.
I got my Rift thinking that I might sell it but decided to give it a spin first. With my DK2 I had already played Chronos and Lucky's Tale. I thought the games were really fun but didn't pack the punch of the VR experience I had with the Vive. I may be in the minority but even after playing the Vive for a full month, when I put on the Rift CV1 I was blown away by its overall quality. I am a video buff and minor differences in quality to others tend to be a big deal to me. I don't even know the specs here but my personal experience is that the visuals on the Rift surpass the Vive's by a noticeable amount. I don't know if it is the lenses, the screens themselves or their calibration. I have heard that the HMD is light and very comfortable but for some reason I never really felt that was going to sway me one way or the other. After playing VR for a little over a month, comfort and weight is a very big deal. I put on the CV1 and it is super comfortable and I don't feel weighed down like I do on the VIve. I remember feeling that way when I first put on the Vive after using the DK2. This was a much larger jump and I immediately starting dreaming about the ideal experience - the Rift CV1 HMD with the light house tracking and motion controls of the Vive. The final piece that makes the Rift superior in my opinion is also another factor that I dismissed early on - the integrated headphones. After playing the Vive and absolutely struggling with the ear buds, they are a very welcome relief and are just there and very comfortable. Sound great too. The ear buds on the Vive keep falling out and are just uncomfortable.
I will not be selling either system, which kind of sucks for my wallet but it is what it is. I want them both, because they are both "better" in their own way. The Vive's tracking is better - plain and simple. Once Oculus puts out the touch controllers, I feel that the tracking will still be superior on the Vive.
That being said - everything else is better on the Rift in my opinion. If I absolutely had to choose one - it would be the Rift (and I shocked to have this opinion).
Question - the tension strap on the Rift. It is supposed to spring back in, correct? Mine appears to be slightly broken and the tension needs to be created with the velcro. It does appear to have some spring on one side, but just a minor amount. The right side has no spring or tension at all - it just glides in and out. I really don't want to return this for a new HMD as I am really happy with the state of the lenses and the screens are perfect.