I understand that roku is a device that enables people to stream various channels, but mine hasn't arrived yet, and I'm trying to learn a little about it ahead of time. I saw MachTV posted somewhere, and at first I thought it was similar to and possible comparable to Sling TV, but now I'm not so sure. I've seen MachTV described as a private roku channel, but I have no idea what that means. Can someone please help me understand the difference, and how each functions? Thanks!