Internet DHCP/DNS issues with WRT1900ac

Question

I've had a WRT1900ac now for about 2 weeks and the problems seem to be escalating.  Need help.  And yes, I've already read dozens of threads about these issues and nothing seems to be working.
Most of the problems seem to be centered around this DHCP/DNS issue that so many have been reporting.
First, the symptoms:
Galaxy S4 phones when connected via wifi have some apps that don't update (facebook and google play)
Some computers (both Win 7) will connect to the network just fine, both wired and wireless - but won't be able to get to the internet
I've spent the last 2-3 days of my life reading forums and trying all sorts of things to get this to work properly (like my old router) and I'm still stuck.  Some things I've tried:
Firmware is up-to-date (latest version: 1.1.8.164461)
Manually assigned static DNS in router config settings (connectivity -> local network) to various combinations including the router address, 8.8.8.8, 8.8.4.4, 75.75.75.75, 75.75.76.76 (I have comcast), OpenDNS addresses, etc.  I read that the router address is not needed, so I stopped including it.
I manually assigned IPs and DNS on the Galaxy S4 phones and that seemed to work... but also seems unnecessary.
I've reserved DHCP addresses on the computers in question, that didn't seem to work, I also manually set DNS on one of the comupters (can't on the other... long story/not my computer) and that worked for a while and then stopped working.
The only way to get one of the computers on the internet now is to turn on the guest network (even though the computer is hard wired to the router), connect, and then the wired network works.  No clue why this is, but my guess is that it needs the guest network for DNS, then it fails back over to the wired network.  Once that happens, I can actually turn off the wifi on the computer and everything works great... until I reboot.  Key point: I can't change any settings on that box other than entering in SSID/passphrase info for the wireless connection.  I can connect to the regular (non-Guest) wifi just fine - I just can't ever get to the internet.
I've tried massaging DHCP settings on the router until I'm blue in the face - Static DNS, reserving DHCP addresses, hell I even put one of the computers in the DMZ to see if that would work and it still can't connect to the internet (it's worth noting that with my old router, Linksys WRT310N, the setup was literally plug-and-play - no hassle with any of this).
I've tried countless router reboots, factory resets, turning off my modem and router for 2+ minutes, and nothing is working.
I even read somewhere that if you modify your DHCP settings at all that the WRT1900ac stops doing DNS properly and breaks, so I even tried several "hard" factory resets and used all the default DHCP/DNS settings.  And it worked... for a few hours.
Seriously, I'm at my wit's end.  I'm out a lot of money on this thing and it's been one headache after another.  Please help.

Answer 1

I think for most people its a bad idea to hold out that hope, lol. It seems like a great piece of hardware but if you really need a router and don't want to have to 'play' with it, its probably not a good choice. I have an EA6900 that I am very happy with but it has the same restrictions as far as DNS and I really hate the idea that I am forced to use the smartwifi portal. I would really like for them to give me a choice of the old gui or the new one and let ME decide. Lots of routers to choose from out there now and new ones seem to be coming out all the time so do some reading and see if something suits you better. Good luck!