I used KeePass with google drive sync before, so cant speak to LastPass.
What got me interested is that Bitwarden is open-source and empowers you to self-host, which for me goes a long way for establishing trust. It has a modern interface through desktop, browser extensions and CLI. You can choose to cloud-host your vault on bitwarden servers, for convenience, with a very generous free tier. Which is what i've been doing for years now, no complaints really.
I can't speak for everyone, but I made the switch after there was some drama with LastPass not reporting security problems in a timely manner a while back (https://news.ycombinator.com/item?id=29737973)
I had used LastPass for a few years, and begrudgingly started paying when they went the "desktop or mobile only" option for free accounts - I need both for complicated reasons. The switch made me pretty bitter with them over the whole thing. It was like I was tricked into trusting them to deliver one thing, then they started to charge me for the "privilege", with no tangible improvement to the service they were providing.
Personally, I've had nothing but great things to say about Bitwarden since moving over. The import from one to the other was pretty painless.
I still have to interact with LastPass for certain job-related things, and the difference is really very noticeable. Much easier to generate usernames and passwords in the web extensions on BW. Things are laid out a bit more logically, in my opinion. It also feels like BW signs in/loads significantly faster in the browser extension (I might just be imagining things). It just feels less cumbersome than LP is.
The only negative I can think of is that LP is a bit prettier to look at.
What got me interested is that Bitwarden is open-source and empowers you to self-host, which for me goes a long way for establishing trust. It has a modern interface through desktop, browser extensions and CLI. You can choose to cloud-host your vault on bitwarden servers, for convenience, with a very generous free tier. Which is what i've been doing for years now, no complaints really.