I ordered a few iBeacons (RadBeacon Dot) for our school history/interactive museum project, and am starting to test them.
So far I'm getting decent results using the intermediate setting.
One glitch, when I went from testing just 1 beacon to 2 was that, surprisingly, both beacons I ordered seemed to have come with the same UUID. This resulted in each beacon triggering both actions I had set up. Took me a bit to figure that out, but I was able to change the UUID of the 2nd beacon using the RadBeacon app.
P.S. With "immediate" setting I have needed to be almost on top of the beacon (about 20-30 cm) to get it to initiate trigger. On this setting, it seems like the player would HAVE to know exactly where the beacon is. So it would probably function pretty much like a QR code (i.e. Walk up to a known/marked spot to trigger something in the game), though perhaps less clunky than needing to exit to the scanner and scan the QR code.