Renovate maintainer and Community manager here

Before I joined Mend to work on Renovate, I wrote https://news.ycombinator.com/item?id=40011111 which goes into some ways I found Renovate better than Dependabot, and it still very much holds true (although I'm a little more biased now!)

You can also check out https://docs.renovatebot.com/bot-comparison/ for a high level comparison between the two

Re costs / why giving things away for free - @rarkins (Rhys Arkins, who created Renovate) has worked very hard over the years to give as much good stuff away to the community, and make it more straightforward for folks to run Renovate

The core (Mend Renovate CLI (AGPL-3.0-only)) is free to use and run as you want, and many folks do - it's very flexible and scales well as-is

But if you want things like real-time webhook processing of "rebase this PR" (and/or a few other features) then Mend Renovate Self-Hosted Community (commercial-but-free) Edition is a nice packaging and layer on top of the CLI for that

Running the CLI itself on a schedule against your repos is also absolutely viable as a solution, and we have many users who do that and are super happy with it