If you're considering Sling, then you should also take a look at the other streaming cable TV services, which also offer cloud DVR: Hulu with Live TV, DirecTV Stream, Fubo TV, and YouTube TV. Each of them has their strengths and weaknesses. Be aware that Sling TV typically does not offer local stations carrying ABC, NBC, CBS, Fox, etc. while the other ones I listed do. Also be aware that YouTube TV doesn't presently have a dedicated Roku app, so you have to access that service through a menu listing in the regular YouTube app on Roku.
As far as getting a Harmony remote to control a TiVo and your Roku, you could, but the TiVo remote is a big part of that device's appeal. Also keep in mind that the TiVo Edge runs the new TiVo user interface (known as "TiVo Experience 4" or "Hydra"), which you may not like as well as the older version that shipped on the TiVo Roamio, Premiere and older DVRs.
Ultimately, though, it just comes down to how much you love TiVo and want to stick with it versus trying other options. (Keep in mind that none of the streaming cable TV services I listed above have a contract, you just pay month-to-month.) Only you know which channels you care about and what the cost would be for cable plus TiVo versus a streaming cable TV service you might choose instead. You just have to do your research, figure out the costs, and decide what's right for you. This website might help:
Suppose... you could design your perfect TV service
As far as getting a Harmony remote to control a TiVo and your Roku, you could, but the TiVo remote is a big part of that device's appeal. Also keep in mind that the TiVo Edge runs the new TiVo user interface (known as "TiVo Experience 4" or "Hydra"), which you may not like as well as the older version that shipped on the TiVo Roamio, Premiere and older DVRs.
Ultimately, though, it just comes down to how much you love TiVo and want to stick with it versus trying other options. (Keep in mind that none of the streaming cable TV services I listed above have a contract, you just pay month-to-month.) Only you know which channels you care about and what the cost would be for cable plus TiVo versus a streaming cable TV service you might choose instead. You just have to do your research, figure out the costs, and decide what's right for you. This website might help:
Suppose... you could design your perfect TV service