Quote: "Are the other engines actually so much better than this one?"
No they aren't. I've used the Gamestudio A7 and Torque engines and despite a seemingly better list of features, it requires too much work for a single developer to reap the benefits of them. The Sauerbraten 2 / Cube 2 engine is the only other option I would say is potentially viable.
Quote: "It seems like you can do lots with this engine"
You can. It's a fully realised game engine capable of producing very high quality games. Sure they might not be commercial quality right now but you could produce something completely unique that is comparable with games made using the Quake3 engine.
Quote: "One thing I note is the file sizes are big.. but Rastaman's file squeezer might help with this"
You can download an application called FPSPack which is now free and will compress your compiled game file size by 50%.
Quote: "Cause if you look at commercial games their filesize, they reach over the 1 gb!"
More like 4 gb for current commercial games. Unreal 2 was 1.4 gb on 2 CD's and that came out sometime ago. There's a lot of talk in the industry of developers releasing games on 2 DVD's at the moment which is the only advantage the PS3 has over 360 in regards to Blue ray storage capacity.
Quote: "Almost worst performance of all "low-budget-engines""
Whilst the performance in FPSC can grind to a halt if you try to throw a large scale scene at it. It's perfectly possible to achieve a game that runs at a constant 30 frames per second with moderately large scenes and high quality details.
It is also receiving a lot of updates at the moment and is getting even better all the time. The community is the best I've come across in terms of support and giving away high quality media which you can use in your own games, although its a lot more rewarding to model your own, especially characters and such.
The community mods are also very good, particularly EFX mod which gives you extremely high quality graphics e.g. water, bloom, moving lights and dynamic shadows.
There is only 1 issue I have on the graphics side of things at the moment which is the lack of a good bump map shader for segment surfaces. Unfortunately FPSC shader programmers are very hard to come by.
Considering it costs $50 / £25 this is the best value for money software you will ever buy and the best possible chance of making your very own high quality first person shooter.
