It depends on what you want to do with it. Personally I think it is the best limiter around. If you are doing a lot of professional mastering work for other clients then I say yes go for it because it is quite amazing. It is capable of reaching some serious volume levels without smashing the mix apart like most other limiters do. It is very complex and you can adjust
10 aspects of the limiting which is not possible on most limiters. It is very important you read and digest the manual as they explain what everything does. You have to spend time tweaking the parameters too.
But if you are just after a quality limiter to boost your final mixes for your own pleasure then I say you may not need the Xenon. There are other great limiters out there for less money than can do that job easily. At the current price it is good value though. I paid the full $249 for it but as I do a lot of mastering work I have never looked back and it has easily paid for itself many times over.
You don't need three limiters either that is rubbish. The Xenon can do every style of music. You just have to know how to set it up properly that is all. I have mastered some serious differences in music genre and it was amazing in all cases. All the great mastering engineers use it apparently!