others says its junk you know?
Its not junk, you just have to lower your standards (still dont get it why is standard spelled with a "d" instead of "t"), if a person has never played cs/hl then they wont get it anyway. The gs engine is probably the best way to train new mappers just because of how easy to start with it is. If you want to develop for it - develop, but what I can say is that with that much coding put in it they would have probably made a better engine themselves rather than wasting time putting work into this one, if all you need is a step up from gs just use source, why bother putting something in the middle ?
Im just rambling right now anyway, short version: want better graphics and that old feel of quake legacy go source, its a bit steeper learning curve due to people expecting gold from everything. Else just stay with gs and lets face it you're old then.