Sounds stupid but i'd recommend a tv you like. Not without reason though. At the very least if you're not only using game mode every manufacturer has kind of a specific picture look. That's not neccessarily bad with 'no name' tv's.
4K or not 4K, you might rethink that some day, so:
That 4K one looks pretty much like one that's sold with another name in Europe. If it is the same picture quality overall isn't the best, looked like scaling deficits. One benefit might actually be it has 4 HDMI ins and at least some of them should have HDMI 2.0.
Here's the but. But there's still many 4K TV's without full UltraHD support. So no high dynamic range for example. And how much resolution you need or benefit from actually depends on screen size/viewing distance ratio.
If viewing distance/screen size is 2 or bigger people should totally forget 'sharper than 1080p'.
One small thing i noticed, the 4K one has 250cd/m2 max. brightness. That's a bit low for lighter environments.
Now the 58": It's a bit cheaper and a bit bigger. It's not that much bigger though. Actually 11% more screen space isn't such a big deal. One real downside, it's got only two HDMI ins. If you're already using an AV receiver that doesn't matter. If not, how many HDMI's do you need? You might ad some HDMI splitters.
If two HDMI is fine for you the slightly bigger one is worth a try. If it's not sufficient for you, spend a bit more money for something like an LG or Hisense (yes, chinese, but they've been getting better over the past years). Seems like Wamart sells some refurbished and not so expensive ones.
http://www.walmart.com/ip/Refurbished-Hisense-55H7B-55-4K-Ultra-HD-2160p-120Hz-LED-Smart-HDTV-4K-x-2K/50213185
About your question:
Got interested in all that stuff when i was 16 i think. Started with HiFi Stereo VHS, Dolby Pro Logic AVR when almost nobody had more than stereo, changed to DVD, widescreen CRT etc. as soon as i could afford it and at some point started building DIY speakers. So in the end i might be just nuts about all that stuff. :p
Don't need the newest shit anymore though but i still like to stay informed.
