No, punkbuster is just a huge 'feel-good-but-do-almost-nothing' pile of software. Especially in linux PB does NOTHING at all to check for hacks.
And after all there are only a few possible cheats.. cheats that improve what you see. If those are necessary its a sign that the basic game has a flaw. Should not be the case in Nexuiz. But i think this will also improved in some later version by being able to force player models on others.
Timers.. that tell you when an item is about to respawn. A big clock beside your screen or someone sitting beside can do the same and basically this is something good players do with some math and the clock in the scoreboard in their mind so this is something that will only help REALLY bad players and is not really worth to even think about it. If someone really needs such a hack you can beat them because they just suck.
Aimhacks.. Well good players are often better then aimhacks and bad aimhack users can be spotted by spectating them.
More over ALL of those three hacks are basically undetectable if done right. If you hack your opengl drivers and input stuff directly into your mouse driver. With the use of a virtual machine you can scan the client computer as much as you want you will not find a thing. Software like PB can make screenshots but normaly they are of a low resolution were you can't see shit and if a hack is that stupid not to work around you will probably also find out by spectating the player.
Cheats that let you see through walls. Those will no longer WORK with the next version of Nexuiz as we prevent the client from knowing were the enemy and items are if you can't see them and hacks can not display stuff that your client does not know about. Basically you can make walls as transparent or non existent as you want it will just not help you as you still can not see whats behind them.
What is better then a arms race to scan for cheats (which you will never be able to win and as mentioned some cheats are undetectable if done right) is to stop cheats were you can like stopping wall hacks from working and making a PITA for those that get cought cheating. This is currently not the case in Nexuiz as its open to everyone. Other games use CD keys which Nexuiz just does not have. Maybe Nexuiz will get a user system in the future which will allow to to ban or punish bad players which would BE a pita for them. The community just has to work together to make cheaters not welcome and make them feel it and make it unpleasent for them to cheat. Such social solutions are way more effective then everything else in my opinion.