In my experience, as another longtime user of vim and now using helix as my daily driver, it does take a bit of getting used to. But once you grok the whole idea of "selection first, then action", it becomes a bit easier to deal with. Honestly I think Helix is a better editor for those who are looking for the features of Vim but don't want to learn its esoteric syntax. I had to learn Vi/Vim in order to work with FreeBSD machines back in the day, and I had a whole book to reference its commands, so for me it's kinda second-nature. But for new users, I can imagine Vim not being the easiest thing to figure out.
I chose to take the plunge and start using Helix most of the time because:
1. It's like Vim/NeoVim enough that I didn't constantly get stuck. Most of the modal commands are similar to Vim, and you can always fall back to mouse-based selection and using normal commands like Ctrl/Cmd+V and Ctrl/Cmd+C if you don't want to get into the registers just yet.
2. Built-in support for the stuff I actually care about. LSP, fuzzy file picking, inline docs, IDE-like features like "go to definition", it's all included. And unlike NeoVim, it doesn't crash half the time when I'm working on TypeScript files (thanks Rust!). Haven't needed CTags at all since I started using Helix.
3. It's fast. Like, way faster than NeoVim or Vim unless you don't use any plugins. And without plugins, it looks great. Tons of themes to choose from, easy to switch them in the config, etc.
> I have a feeling that movement-action paradigm as opposed to action-movement paradigm of vim will have some tradeoffs with visualisation being a plus, and more advanced repetitions bring a negative, but I haven't totally thought this through.
I think the "advanced repetition" side of this is just going to look different, more like Emacs or Sublime Text in its functionality IMO. For example, the "Migrating from Vim" guide mentions global replace (https://github.com/helix-editor/helix/wiki/Migrating-from-Vi...). This doesn't really go into how it looks, but what happens looks a lot more like NeoVim than Vim. It's still just as fast as Vim to write these commands, albeit a different syntax that you have to get used to, but the benefit is being able to see what is happening to your file while it's happening, rather than after the fact or having to jump through every instance and "confirm" it (which is problematic on large files). In other words, I think this will be/is possible to do in Helix, but it will just look a little different than in Vim.