For 30 bucks THIS ONE is better if you are in a hurry. If you aren't in a hurry, BoboVRZ Z4 is better (but you have to order from china..aside from the occasional amazon/ebay)
I have a Nexus 6P. I started with the Unofficial Cardboard 2.0, which is neat, but didn't meet all of my needs. I upgraded to a LeNest / Fiit (and the LeNest external controller), and I've been quite happy with it. Really, I couldn't see buying another unless this one breaks or something.
Edit: For reference, this is the model I bought. LeNest 3D VR Headset-GEAR+ Virtual Reality Headset Glasses,works with 4~6 inch Smartphones,Light weight can play and watch comfortably, Beginer for Samsung Gear VR https://www.amazon.com/dp/B01B755CV8/ref=cm_sw_r_other_awd_QFOfxbJW8JM6N
There are two LeNest models floating around. One is basically the BoboVR Z3, as /u/3015 mentioned, the other is it's own model.
I have tried the OtherVarient, also goes by "Fiit" and other names. It is ok, but isn't super comfortable. Also, it's sweet spot is very small. I haven't tried the first, but if it is a direct rebranding of the Z3, then it's an ok viewer...if your phone has a 7 inch screen.
You have a pretty small phone for VR - there are no viewers that would make your phone fill the whole view AND give you a good FOV. Are you handy?...as in, would you be willing to get a viewer, and then to alter it by gluing in a second set of lenses? The Z3 with extra lenses would be pretty good for your phone.
BoboVR Z4 should have much better lenses and overall than the Z3. The issue thought is that your phone is still pretty small.
I'm actually thinking that you should try the LeNest/Fiit viewer if you can get it from amazon prime (and return if it doesn't fit your phone)
Overall, cardboard v1 might be your best bet just due to the size of your phone. You can alter it to make it more comfortable by adding cushion, cutting out some slots, etc.