When comparing KeeWeb vs LessPass, the Slant community recommends LessPass for most people. In the question“What is the best cross-platform password manager?” LessPass is ranked 13th while KeeWeb is ranked 24th.
Ranked in these QuestionsQuestion Ranking
Pro Its password databases are compatible with those of KeePass 2.x
KeePass 2.x *.kdbx password-databases (provided they are encrypted by AES-256 with AES key-derivation) are compatible with KeeWeb.
Pro Supports WebDAV, Google Drive and OneDrive
Pro Available as an online or offline app
There are Windows, Linux and Mac OSX offline apps.
Pro Syncs with Dropbox
Pro Supports 2FA
And it's Google Authentication compatible.
Pro Open source
Pro Really platform-free
Pro Doesn't store passwords
If it's not stored, it can't be stolen.
Con Drab interface largely devoid of color
Con Cannot store existing secrets
Existing secrets (aka passwords) cannot be stored with deterministic password managers. In order to use LessPass effectively, you will need to change your password on every site.
Deterministic password managers have many drawbacks.
Con Easily cracked with exposed/compromised master password
Since anyone can use LessPass with the same parameters as you, all they need is your master password (which could be obtained through keylogging or numerous other methods) to gain access to every one of your site passwords.