How many people are looking at alternatives to pay TV?
A couple of years ago, I looked at the $100/month pay TV bill and determined we regularly watched less than 20 hours a month that wasn't available over-the-air or from one of our other sources (Netflix, Amazon Prime Video)--ignoring cartoon channels. (That was before Mythbusters was on Amazon Prime.) I boosted the internet speed and dropped the TV subscription and set up a media server (Plex on Ubuntu with a few TB of RAID) so I could deliver the video collection anywhere in the house easily. We haven't regretted the change. We spend less time watching TV, more time doing other things like reading, playing games, writing, etc. Some of those are still solitary pursuits, but probably healthier than watching TV. (Especially when I consider how much I ate in front of the TV but don't eat now. :) )
What are you experiences? Why have you or have you not cut the cord? Thinking about it?
There's some software called PlayOn that actually supplements channels using scripts. It's $40 a year I think.
I go back and forth with cord cutting too. I've tried it in spurts and it is a lot to ask my wife, who is not technically inclined, to power on the TV, set the receiver at a certain channel, or power on the Xbox, navigate through the console GUI, make sure the PlayOn service is running on the hosting PC, etc etc just to watch television. She just wants to turn it on.
I don't have my whole house wired to UHF and a high def antenna, although I would like to one day. We actually have Roku, Netflix, PlayOn supports the FREE Hulu (which is really nice). Sports are tough though.
The HD tuners will get channels depending on the direction its facing. Not sure if weather is a factor though.
Fortunately, I'm not afflicted by the sports demon. :) But I know many people are, and that is one of they key roadblocks for many potential cord cutters. You say you have Roku. They do have MLB, NBA, NHL, and some college sports, but I think NFL is available only on broadcast/pay TV.
PlayOn seems to have a Roku channel. I don't know what it looks like. I think if I were going to go the PlayOn route, I'd try to set up a machine to run it and have it up 24x7. That eliminates the need to find the PC and make sure it's running (unless Windows crashes), which is probably the biggest inconvenience of the process you outlined. (I wonder if I can get it running in Wine on my Linux server... but I'm not sure why. I don't need to spend more time watching TV. I'm doing many more creative and interesting things now that I'm not in front of the TV so much.)
You could also set up Windows box running Plex (which will index your local media and stream it over Roku and other clients) and try the PlayOn plugin (which I haven't tried because I run Plex on Linux). That would put all your non-broadcast TV and local media in the same place (a Plex client). Or run both Plex and PlayOn on the same machine.
This brings up an important point, though. Cord cutting may cost more up front to set up a system that's going to work and be easy to use (if you're not forgoing TV completely). An antenna will run you $30-$50. If you want a media server of some kind, expect to spend $500-$750 on hardware plus clients ($60-$100/TV), and possibly network cabling (varies depending on what you're doing). If you're paying typical cable rates (around $100/month and rising) you can usually recoup your investment in less than a year, but that "what's it going to take" and "when am I in the black" analysis should be part of the planning.
Another point is to prove out the tools and technologies you plan to use with the least investment possible before cutting the cord (sounds like you've proved PlayOn can meet your requirements--except for sports) and make your environment consistent (give all your TVs a Roku box or give them all an Xbox so the interface is the same on all of them and they all have the same capabilities).