yea, its about preference mostly. Theres ones like orac, which are a huge tangled mess, but still look amazing (the tangling mess was the theme) and then theres ones based off things, like off games and such. I saw a guy who build a post-Chernobyl accident reactor for stalker. Looked amazing, not my thing though.
The amount of work some of these guys put into there mod is just unbelievable. The guy who made orac said he spent like 10 grand and over 500 hours