Scrivener is pretty great! I've used it for a number of years now and there is much about it that I like. The two main features that I love:
1) that it is so much more than just a text editing program, as it gives you a framework and space for you to organize all sorts of different background elements to your story (and include all sorts of things like character photos you find on the web, links to things, lists of characteristics, and plot notes etc. etc.).
2) You can write in whatever font and size you like and then save it out ('compile') the manuscript super easily into whatever format you want (there are tons of options)- using whatever font parameters you want without changing anything of the manuscript in the process.
All that said I know maybe 10% of what scrivener can do. I have it set up in a way that I'm used to now, but I get the sense it's a Ferrari that I just use for making trips to the laundromat - kind of thing.
And thanks for the comment link! I'm guessing though that it would work great for me to make my own comments but any Beta readers would need scrivener themselves (and all my source files presumably) to be able to use that to make comments back that I could use. I'm pretty sure that scrivener can export to word doc files super easily so if that's what most people use that might be best(?)
Have a great road trip Joshua!