Nexus 5x here, that headset is the same exact one I bought only with a different branding and a higher price. Overall it's a great headset with adjustable lenses and a head strap, mine came with a screen cleaner as well. It's fairly comfortable but does press on your nose a bit. Only complaints is that you have to take the headset off to adjust the lenses, and that theres no button for you to click. I purchased a ps4 controller which takes a bit of fiddling to connect but works great with all the games I've tried that have controller support. However there are some apps that don't have controller support and require a 'tap', so a cheap bluetooth controller might come in handy, i purchased one thinking it would work for games but aside from using it to simulate a tap it's actually pretty laggy(why i got the ps4 controller).
Here's a link to the headset($24.99): https://www.amazon.com/dp/B01C5IXFI8/ref=cm_sw_r_cp_apa_AvI4xbPAHN26G
And a link to the controller i bought: https://www.amazon.com/dp/B01ELDVFVY/ref=cm_sw_r_cp_apa_qDI4xbVWFG02D
I'm on my phone so sorry for shitty formatting, hope this helps.
EDIT: Not sure how big an S5 is but this headset will benefit from a larger screen, almost made me wish I got a 6p instead.
TBF any device you can get that uses your phone as its screen is utilizing the Cardboard technology.
Yes, google does offer a cardboard version of the VR viewer, but as you are aware, there are thousands of these plastic headsets available, with differing options and quality.
The one you bought is ok, but I don't think it has pupil adjusters for example, and having those make a big difference.
If your plan is to use Cardboard over the more expensive Occulus or Vive VR, the highest quality headset you can buy is the Samsung Gear VR headset.
Other than that, you are pretty much left with 3rd party headsets online. I bought one not long ago and really liked it, https://www.amazon.com/dp/B01C5IXFI8?psc=1 but there are better and more expensive ones on the market. This one has everything I need - without going overboard on price.
Hopefully you haven't bought anything yet, because this is a much better deal: http://www.amazon.com/gp/aw/d/B01C5IXFI8/ref=mp_s_a_1_12?qid=1460075389&sr=8-12&pi=AC_SX236_SY340_FMwebp_QL65&keywords=vr#nav-search-keywords. Review: http://www.hypergridbusiness.com/2016/03/review-lenest-viewer-is-close-to-perfect/