Not me. I won't pay $400 to swap out my 2 original Hoppers that are less than a year old. I already have Sling adapters on both of them. The only thing I would gain is the transfer feature to our family's iPads.
I would like the transfer feature because our cabin in Northern Michigan is pretty cut off. We only get OTA TV there, no home broadband, and the cellular coverage isn't reliable enough for video streaming, although it does work fine for Pandora and MLB audio streaming. We spend practically every weekend up there during the summer on the lake so it would be nice to load up our iPads before we go. However, it isn't worth $400 to me.
In just about any other situation I am regularly in we can use WiFi or LTE on our iPads and stream everything with sling so the transfer wouldn't be necessary. A better solution for me would be Verizon putting a nice LTE tower in at the lake. That way I could stream my Tigers baseball video live instead of just the audio.