If I want to develop a serious game/app, which one am I supposed to use, BaseGame or SimpleGame?
The choices are generally between SimpleGame and StandardGame… When you say ‘serious’ game or app, my mind jumps to StandardGame as its cooperative in terms of multi-threading. It’s also more difficult to use, but does have many payoffs. I’d highly suggest reading the brief on it here
In any event, it would be helpful to provide some detail on the scope of the project that you’re planning on embarking on (OpenGL GUI?, canvas or no canvas, networking, etc).
An online FPS Game is what I am planning to do, but Standard Game is more difficult as you said. But I don't know which one you guys preffer if you would use a Networking system.
You might find it interesting that the person who wrote Java Game Networking (JGN) is the same person who did much work on StandardGame
I am personally using StandardGame on an MMO project. It's important to note that it isn't avatar based, so you aren't seeing other characters running around, but StandardGame is allowing much flexibility with how we configure the system. Some network transactions, for example, involve transactions of large amounts of data and offloading this to another thread is essential to keep the scene live while other background processing is going on.
I also like the explanation that has been offered before of StandardGame as a bunch of SimpleGames. When thought of in that context I find that it offers many opportunities for scene management that would otherwise be difficult to implement in a vanilla SimpleGame.
Addressing the difficulty of use concerns, yes they are indeed there. GUI systems like FengGUI can be a bit tricky to get working correctly, but they do work and there are examples of such integration in the wiki as well as many seasoned folks around the forum