Don't buy one they're no good.
NO......wait, I've got one. In fact I've got the first one out the door and it's amazing.
I wouldn't part with it for anything.
If all you want is amazing ballistics and long range killing power in an easy to handle gun then it's what you're looking for.
Like was mentioned, in addition to BB's links, use the search feature and get ready for a lot of reading.