Here is what @lunaticpandora said earlier today in a comment to this post:
I personally had struggles switching from steemit to busy because it lacked a night mode but i managed to solve that by installing a chrome extension called dark reader and it has been the best decision i've ever done since joining steem!
I don't consider it a major inconvenience though.
I don't switch to Busy precisely because of the lack of a night mode. I do have an extension like @lunaticpandora that allows me to artificially induce it, but it doesn't look as well as Steemit's night mode.
Also, the Steemconnect requirements for all transfers and operations slow down everything that I want to do. I can't "hurry up and transfer", I depend on Steemconnect, which is very often slow.
It's also a bit buggy sometimes and doesn't properly open up some threads, it has a "slinkier" functionality that makes it more prone to failure.
I prefer the primitive behaviour of Steemit for now, and I'd like an even lighter site with more information but less technological requirements like Ajax requests for every tiny little thing, wallet limitations (like Steemit that only has a few days of entries now instead of the whole transfer history) and 2-digit limits to rewards.
Ah gotcha, gotta love that night mode :D.
Luckily, Steemit provides you with all the features you prioritize in your casual interactions with it. I've been using it for over a year now and it got quite stale.
Let's see what I have to say after being a Busy user for year, but so far I've been happy with my experience.