At a previous job we rolled out Ubiquiti APs on one site since they were so inexpensive just as test to see if we could move to a controller based system. After the second AP failed of the three we purchased we went with a Ruckus system despite the increased cost. We chose to spend a bit more for apparent reliability.
That said, for my current job I've chosen to do a test deployment of UBNT hardware.
Weird - where did you buy them from? Failures do happen, but 2 out of 3 failing.. that's pretty bad.
I deployed UAPs (22 and no failures) and it has worked flawlessly for me for 8 months so far.
This was 2012-2013 time frame, so given the average experience I'm not knocking them off the list permanently.
They were off of Amazon. From UBNT iirc.
The ERL in 2012/2013 was iffy. But not the basic UAP. interesting experience.