For those who don't know. I would to like to say that L2OFF speaks for itself. L2OFF were built initially by NCSoft (Lineage 2 Official Producer).
The L2OFF we have available, currently have more fidelity to the official servers gameplay themselves than L2 Java.
Remember guys, L2OFF, generally are made by people wich understands C++ and Assembly languages, the main programming languages used by NCSoft (chose on purpose). People who built the core on Java were trying to build the Lineage 2 core by easier means languagewise.
L2OFF can be harder to mod, apply features and all that shit, but it shows a LOT more performance, a LOT more mechanics/interaction/fidelity and I'll not even mention stability.
So the point here is: If you want a server for providing best fidelity gameplay experience in therms of performance and stability go for L2OFF. It's harder, an art but tough path tough.
If you want something to mod, apply changes, faster content updates, and a easier path go L2J.
If you compare the actual L2J execution structure to a L2OFF execution structure, you'll easily understand the strong and weakpoints of both sides.
I would argue that to put players to use the game client for playing without a connection to a NCSoft licensed server is illegal anyway. Don't miss that point.
And remember. I'm not making any kind of advertisement for any platform.
I just had a time here to justify that it is easy to say that something is shit/trash when it doesn't fulfill your needs. And if you spend time studiying stuff you'll learn the where and whys of them.