From what I've read the earlier models were kind of crappy. They used 3D printed parts that had low tolerances which resulted in a shaky printer. The earlier models also didn't come with any build instructions.

After a few revisions the kit has gotten a lot better. The frame parts are injected, it has a redesigned effector head, a bigger power supply and it also comes with build instructions.

The thing is, it's a kit. Stuff is bound to go wrong in something as complex as this. Anyone who gets it right the first try has probably made one already. If this is your first, don't expect it to be perfect without a lot of meticulous research and time.

http://www.reddit.com/r/3Dprinting/c...ssel_kit_from/
http://3dprinterblog.net/comprehensi...kossel-review/