ORMs are almost always a bad idea. They add an unnecessary layer of complexity which will result in both speed and space inefficiencies. If your project is small just use SQL, it will be easier. If your project is large you will end up writing a lot of customized SQL anyway, so just use SQL. If your project is in the middle, will never become large, you won't have to support it later and you already know the ORM tool then you may benefit from ORM.