Wow that VIVAX case looks insane. Super cool, but I do have to agree I don't see what makes it that much better than the Pelican.
My wife and I both have 15" Retina Macbook Pros and we both use Pelican cases for them. I have the Pelican 1095, the version with the pick & pluck foam. I fitted the foam perfectly for the size of the rMBP (length, depth, and height) and it fits amazingly. I have about 1" of foam around all surfaces along with the crush proof case, I feel very confident about the protection of my rMBP! I travel a lot for work, ride my bicycle, and motorcycle - in all situations I would never go anywhere without my rMPB in my Pelican case. Its been accidentally dropped with absolutely zero damage. I freaking love it. I tell my friends that it is my own personal AppleCare.
For my wife, I got her the Pelican 1085cc which is a little smaller and less bulky, because she wanted it to more easily fit inside her backpack, or just easier to carry around. The 1085cc is the version with the molded foam liner. The 15" rMPB fits perfectly in the bottom liner. There was some extra room in height in the case, so I ordered the extra foam to put in the top of the case to prevent it from moving up and down. While the 1085cc doesn't have quite as much extra foam around it as you do with the 1095, I still feel very confident about the safety of the rMPB.
Heres a good link with detailed photos of the 15" rMBP in the 1085cc:
http://joshaust.in/2012/11/extreme-protection-for-the-15-retina-macbook-pro-from-pelican/
Overall, I cannot recommend the Pelican cases enough. If you take your Macbook with you a lot, travel with it, bike, or anything...the Pelican case is the way to go. It does add bulk and weight for carrying around, but I am totally willing to deal with the extra bulk and weight for the benefits and protection. I've had my Macbook in the Pelican for 2 years now and it looks brand new, even after dozens of plane flights, motorcycle and bike rides, several drops. I'd be happy to send pictures of the fit of the cases if anyone would like to.
B&H has the best prices on these cases I've found. Only about $65!