It's worth noting that it is sometimes possible to make Channels work reliably over WiFi, even in congested areas. The key thing is to make sure you select underutilized WiFi channels that are not already congested.
I live next door to a new apartment building with over 250 residential units. As tenants started moving into the new building, I found that my WiFi performance was severely degraded.
After checking channel congestion using iStumbler, the problem became pretty clear: the non-DFS 80MHz-wide WiFi channels (36–48 and 149–161) were all massively congested:
This wasn't too surprising. Most WiFi routers, particularly those issued by ISPs, will auto-select channel 36 or channel 149. In the United States, regulations don't require DFS to use these channels, and both are wide enough (channels 36–48 and channels 149–161) to support an 80MHz width for higher maximum upload/download speeds.
My WiFi router at the time couldn't be configured to use DFS channels, so as an interim solution, I configured it to use channel 165. Channel 165 is typically less congested because it falls just past the spectrum used by a 80MHz-wide WiFi network on channel 149 (which spills over to channel 161). The problem is that there are no channels above channel 165 to spill over into, so a network on Channel 165 is limited to the minimum channel width of 20MHz. This reduced my maximum bandwidth to about 100mbit/s but it also made the connection extremely stable and reliable. That change was enough to make apps like Channels work perfectly, and I was able to do it without having to buy or replace any equipment. This strategy would also work even in places where DFS channels aren't available due to nearby weather radar.
Now, I use a better WiFi router (a Synology RT2600ac) that can be configured to use specific DFS channels. I configured it to use channel 100 with a 40MHz width. You can actually see my network in the iStumbler screenshot above—it's the tiny bit of congestion on channels 100 and 104.
With this setup, I reliably get my full internet speed over WiFi. For a while, I was even using WiFi to connect my Mac Mini DVR server to my network. With tuner sharing enabled, this setup still worked flawlessly for me... despite having over 250 next door neighbors. I ended up running a wired ethernet connection to the Mac Mini just for peace of mind, but I probably didn't have to.