To my dismay it was even worse than the first phone. This one was 4 degrees and as high as 5 degrees off out of the box. (The initial phone was 2-3). Was also still having major lagging in the parallax effects.
Obviously irritated I went back to the Apple store and spoke with a manager. He wasn't too pleased with having to replace a brand new 5s for the second time in a day. He went and got (assumed) his 5s from the back and put it next to mine. He spent a good 15-20 minutes sitting at a table trying to match calibrate both phones. (His constantly said -1 or -2, and mine constantly said -4). He was trying everything he could to make them match so he didn't have to replace. He kept saying that it was normal for new software to be glitchy and that this was a minimal issue.
I'm still less than 7 days from delivery, so he told me I could have another one, or he'd order one but I had to make a choice. He still said he didn't think a replacement would fix anything. I pressed for another new phone today very calmly and politely, and he made me wait 45 minutes for a genius table to open up. (*That's another story for another day

) So I left and went back for the 3rd time today an hour later.
Tech comes over, cool kid obviously been briefed from manager, and gets a new phone out of a drawer this time. (Last phone was brought from the back). Instead of walking out without even powering the thing on, we sat the phone on the table and immediately it snapped to -1 which at this point I feel is acceptable variation for an iphone out of box. We calibrated several times and always went back to -1 or even a brief 0.
So it looks like there are phones out there that will be close to zeroed when it comes to the Gyro/Compass. It also looks like there are plenty that are 3-4 degrees off.
As for the parallax, on this phone I'm still seeing some hang/lag and I truly hope this IS a software issue and not an M7 glitch.
Can't hear as loud of internal rattle when shaking, but still a bit loose sounding in power button & home button compared to 5. After testing every phone in store lol I'm assured that this is the new design of both parts.
***Manager stated that having to constantly recalibrate the compass is a known bug for whatever that's worth. He also said Apple hasn't stated anything official on any of this. It's my assumption it's starting to become widespread though, judging from my experience.
In the end it wasn't the best experience I've had with Apple CS, but I still made a point to go find the manager and say thanks before I left store. It's sad but not a lot of companies would sit and hand a customer $2400 worth of product to satisfy their complaint, no matter how wrong they were. So I can still give Apple credit and say this is why I purchase their products.
Hope this helps anybody having same type of issues. It'll be interesting to see what some of the next iOS updates do to Parallax & overall operation.