Some channels are instant on TVE, some are slow. Is it the person's hardware, The particular web page, other factors? Also what is the cutoff for a weak antenna signal to default to TVE?
I would imagine any and all factors would play into this. Internet speed, network speed / latency, wireless or wired, antenna signal for OTA, what streaming device, etc.
The instant TVE channel changes I'm thinking are because the authorization to watch that channel dealing with the cookies / chrome didn't need to be refreshed, but a TVE channel you haven't watched in a while, and / or it's token / cookie / whatever it is has expired and would need to refresh it's authorization thingie, adding to the time it takes to tune the channel.
I just timed mine. I predominately watch OTA, all of which are good signals. None of them tune instantly, however. They are all somewhere at around 2 to 2.5 seconds to tune.
These are all mpeg2. I imagine if yours are taking much longer, it is probably poor signal quality. If TVE, it is either an issue with the speed/quality of the incoming internet stream or the TVE authorization causing a delay.