It seems like AT&T, T-Mobile, and Verizon support it in the US. For US-based folks, this will probably be helpful, as it will allow you to have your incumbent carrier on the eSIM, then put in any microSIM from another provider. Although, T-Mobile has made it especially easy to do away with the dual SIM concept with their DIGITS app. Now I don't have to forward my TMo number to my Google Voice, and I have three phone numbers on one phone.