sqlite: impossible to edit when server is online(good in security, bad when you want to fix something quickly without restarting server), some queries from lua scripts may not work or may not be accurate
mysql: possible to access via phpmyadmin/other tools(?) and can be edited when server is online, if you don't secure it by dropping 'pma' user and some shit some noobish hackers can edit players, accounts(which means they can get god), houses, house items, guilds and other things you have in sql