This is the most powerful gun of the CPS-line, it delivers more water much further than anything else.
But there is a prize to pay for this: it drains its pressure tank more quickly than any other weapon I have ever used, it tanks very long to pump up again and won't give you many shots.
You should never keep the trigger pressed down, always go for quick bursts by just tapping the trigger.
It is best used while having cover from some other medium weapons (CPS, big XPs), as you can use the superior range of the 2000, but don't have to worry that much about being vulnerable while pumping.
Pumping will be much quicker when keeping the 2000 pointed downwards.
Try to keep it pumped all the time, but never overpump it or it will break.
The CPS-2000 is one of the most useful guns in big CPS fights, but must be used very carefully to use its strength.
On its own it can loose against smaller guns quite easily, because it uses its water up so quickly, its pressure tank can be drained in one single (still short) shot and it is quite bulky (identical dimensions to the CPS-2500).
One of the most interesting questions is, why Larami stopped making it. They say, because it was replaced by the CPS-2500, but many supersoaker fans don't believe that, as many don't consider it to be an adequate replacement.
Some people claim it was discontinued, because it was too powerfull (hence dangerous).