I got mine activated with no issues tonight at the sprint store. I went in and asked for the sim card for the s4 (didn't mention the nexus 5). He came back and said I need to see the phone to tie the IMEI to the sim. I whipped out the nexus 5 and assured him it would work. He proceeded to scan the IMEI and scan the SIM tieing the 2 together. He then swapped phones on my account. I was in and out in 20 minutes with a fully functional nexus 5 on the Sprint network. Based on the conversation he was led to belief the nexus 5 would need a special sim card and the s4/htc one sim card would not work. In the end we were both happy...