Q1 and DarkPlaces are so far apart it's not even funny.
While DP was developed over Q1, it has been changed and tweaked so extensively that, when looking at the code as well as abilities, they bare no resemblance.
DP is one of the highest end engines out there, commercial or GPL. But it's very resource hungry.
Also, don't judge DP by Nexuiz. Nex needs a graphical overhaul in terms of models and animation in order to really shine.
Check out Zymotic to see what DP can really do.
@Caveman
The invisible bug was fixed in 1.0.1, 3 weeks after the initial release.
The only way to go invisible right now is to pick up a Invis powerup and that's a feature.
Check your client and see what version you have.
2 things that are great about Nex is the phenomenal community and frequency of updates. There is a patch every 1-2 months (sometimes faster) so bugs and issues are taken care of almost immediately.
The main reason for the great community is the fact that 70% or Nex players are 22-34 years of age. Not 12-17, like the majority of GPL games.
You'll have a hard time finding flame wars or cretins anywhere on the forum or in-game.
@Death On Ice
Make sure you don't call Nexuiz "freeware" on the official forum. You'll be given extensive examples, links and reading material explaining the difference between GPL and "freeware/shareware"