...TiVo has A LOT of apps. It now supports Amazon Prime (Before just Instant). Ever since TiVo adopted the OperaTV store, TiVo has many games, apps and most of the better apps already available on Roku. The $15 sub price is a bit expensive but truth is no other DVR solution comes even close to TiVo as far as universal search and DVR functions. And with all the apps available for it, it makes for a great stand-a-lone product for cord-cutters. IMO, if you can afford it, get a TiVo with lifetime (HD, Premiere, Roamio) but although expensive at $15 per month it is a superior product worth paying a bit more for.
My only "beef" with TiVo is that it cost too much to add multi-room and remote access features by needing to buy TiVo Mini's and TiVo stream. In my home we use TiVo as primary DVR and Simple.TV and EyeTV as secondary DVR solutions for multi-room viewing with Roku's and remote access. A 1st gen Simple.TV STV-1000 for $100 with lifetime is better and cheaper for collecting shows, remote access and multi-room with Roku but the experience is so much better on TiVo on a main/primary TV.
Hope this clears misconceptions regarding TiVo. Yes, expensive but worth the extra money IMO if you can afford it.
Oh, I agree that TiVo is a great service. But, yeah, expensive. I have a Premiere box with lifetime service (in addition to a Roamio OTA), and really enjoy the service. I've used Simple.TV, as well as a Windows Media Center setup. While they do work, they pale in comparison to TiVo.
I've used some of the apps in the Opera Store, but nothing that I kept. Honestly, it has enough apps to do what most people want a DVR and streaming box to do. But that $15/month service is the killer. Without it, TiVo couldn't survive. And, if Roku went down the DVR path, we'd end up with a TiVo Roamio OTA in a more compact form. And a monthly service in the $12-$15 range. That's why it won't work.
Ah, but back to the topic/title of this thread. Roku 4.
There may be something that bears that name at some time in the future (the 4K machine, perhaps), but no one that knows can say, and those that will say don't know (or would be violating NDA).