Reliability of Ebay bought NRF24L01 radios?

Has anyone else had reliability issues with these inexpensive NRF24L01 radios from China (off Ebay)? I had them communicating with each other via the example Mirf sketches just fine and they work intermittently at best... I've bought 3 pairs and have swapped them back and forth and they're all the same... some don't work at all, some work sporadically. Could I be doing something wrong? (I'm using the basic Ping Client Mirf examples in the 0023 library)

If you've used these radios and haven't had the issues I'm having; where did you buy yours?

If you've used these radios and haven't had the issues I'm having; where did you buy yours?

I've only used XBees. Very reliable. Of course, you get what you pay for.

I use the ones from Sparkfun with RP-SMA.

https://www.sparkfun.com/products/705