Here is the thread that originally said the issue was solved.
https://discussions.apple.com/thread/5762493
OK, so here's the deal on this once and for all. ignore anything else you read about this because this is the correct 411:
I used the new NetGear NightHawk and hooked it up to my Router (The Nighthawk is replacing the Airport Extreme I was using, that didn't provide enough range for my liking).
I then took the Airport Extreme and reset it to factory defaults using Airport Utility from my iPad Air. This was a hair tricky because I thought I could just plug the Express in and the Airport Utility would find it, but it didn't. After some fiddling I ended up taking an Ethernet cable and connecting the Express to one of the LAN ports on the new Nighthawk, at which point the Airport Utility on my iPad Air then found that bad boy.
Once the Airport Express was set back to factory default, I then used the Airport Utility to have the Express "Join an Existing Network" (this being the new NetGear WiFi network). If you need to know how to do this, just search for it here, or Google it and you can find the steps.
At this point I was following instructions I had read about putting the Airport Express in 'Bridge' or 'Client' mode, but for the life of me couldn't find a setting like this in the Airport Utility. After some Googling, it turns out that once you reset the Airport Express to factory defaults and choose the "Join Existing Network" option, that in fact puts that puppy in Bridge mode.
I unplugged the Airport Express and disconnected it from the new NetGear router.
I then took the Airport Express and set it on top of my XBOX 360 in another room way on the other side of the house, and plugged the Power in. it took a minute, but by-golly that light on the front turned green. I then plugged the Aiport Express into the XBOX 360 via an Ethernet cable (use the LAN <-> port on the Express, not the WAN port).
I fired up the XBOX 360 and it immediately logged into XBOX Live and it's working like a dream. It may be worth noting that I did follow some instructions in the NetGear manual about setting up priority using the QoS settings, which prioritize the signal for gaming, surfing etc.
So basically the NetGear router will talk with the Airport Express (atleast for this XBOX Live bridge-mode scenario here). Also, the XBOX Live will work with an Airport router without any fiddling, so any incompatibility issues that used to exist are now gone and the two are friendly together.
Sorry about this long drawn-out explanation, but I sure could have used this when I started my endeavor, so I hope this helps someone someday too.