RapidWeaver without it’s addons would have gone out of business years ago. The base products UI hasn’t changed much in its 15 year life. RapidWeaver out of the box isn’t built on a responsive framework like bootstrap.
I’ve only been using Bloc’s for a few months, and I’ve seen @norm add more new features than RW has in the last two major releases.
If you’re not familiar with RW, it’s near worthless without a minimum of the stacks plugin ($50) and a bunch of stacks addons($100’s) alongside a purchased theme or framework.
I don’t see Bloc’s going that way as Norm continues to develop new features built into the base product. I’m looking forward to the new API, as well as Blocs 3 that will be utilizing the latest bootstrap 4 framework.
I’m also waiting for the new preview app coming soon I hope.