See that’s my point. My old cable DVR didn’t have this lag, yet I could still pause, rewind etc.
Yes, if you want instantaneous tuning then you should get a TiVo Bolt ($900 for it with the lifetime sub) for the main HDTV and a TiVo Mini ($150 per device which includes a lifetime sub) for each additional HDTV. The TiVo Mini plays back whatever is recorded on the TiVo Bolt. The TiVo records the OTA stream in the native MPEG-2 video thus there is no transcoding and no waiting for the channel to tune. You will not need a Roku for playback either.
You can still pause and rewind with with the Tablo too without lag.
Yes, that is how the Tablo works. If you have a quad tuner Tablo for example and are recording 4 shows at once, then if you tried to watch Live TV on a Roku you would not be able to tune the Live TV channel because the 4 tuners are being used for recordings and none are available for Live TV. Of course, this is only true if you were trying to watch something else that was not currently recording at that instance, like a 5th show.
Watching a show that was previously recorded does not use a tuner though, as in if you are watching a recording that completed the day before that does not use a tuner.
Read all these simple explanations directly from Tablo if what I said was confusing:
http://support.tablotv.com/hc/en-us/articles/201962858-How-many-streams-does-Tablo-record-per-tuner-
I have been eyeing it 
It makes little economic sense to buy a lifetime subscription for the Tivo Bolt. You have to own it for 6 years to save any money over paying the yearly cost, and what piece of technology would you still want after 6 years? Just pay the $150 cost per year and then switch it out for whatever new Tivo is out in 2020.
Agreed. I would never pay that much money for a TiVo. The Tablo is priced just perfectly.
Well, I’d prefer the Tablo be $100 less, but yeah, I can’t get over the Tivo cost of entry, and then the care and feeding…
Not sure if it’s still the case, but I got a serious reality check with Tivo years ago when I read that their “lifetime” offers were for the “lifetime of the device”, meaning if it gets fried from a power surge, you get to pay for another lifetime. The only transferability was if the unit was replaced under warranty for a covered issue.
I don’t expect ANY modern electronic device to live longer than 3 years … either due to device failure, or industry change leaving it obsolete. That is why I am paying yearly subscriptions for my Tablo … I figure 3 yearly fees = lifetime = breakeven … I may be surprised / dissapointed in 3 years, but figure by then, lots of things may have changed…