I got one for basically free on CL and slapped some parts i had laying around. The gun is really fun to play with. Everything is standard so it's easy to upgrade. AC barrel, standard VASA, ion threaded feedneck, autococker detents and an integrated dovetail on the frame are all very nice touches. They are more than 'spyder clones'.
This marker is higher quality than anything spyder ever put out (maybe way way back in the day they put out something good).
All that being said I built my kaos essentially how the KDII is setup. So if you went for the KDII there wouldn't be any real need to upgrade anything. With the zero kit they are actually pretty quiet and very very smooth little guns as well as very light and pracitcal.
It's a mechanical marker, use your head it's not going to compete with DM's, Geo/ego, luxe what have you. But they are a damn good recball/senario gun. This is my backup (to my automag) and loaner. Great gun.
A couple of items I wish someone had told me
1. if you break a ball in the breech it's going to ruin your game. The gun will be inoperable until you swab it. Always carry a squeegee on the filed with you so you either clean it on the field or on the sideline and jump in on the next game
2. When changing the striker o-ring always take the frame off, the oring will get caught on the sear and tear or damage it causing you to have the same problem you did before. (recocking issues).
3. I don't like to use a force fed loader with mine. I feel like putting unnecessary force on the ball stack will lead to breaks with this gun, the bolt is a little bit too short causing some rollback and stack clipping issues. I use a proto primo or a revvy when playing with it.
I would rather own this gun than any of the comparable mechs in it's pricerange, just my 2c and experience with the gun.
This is why I can't have nice things.