depends on the KO, really. there's stuff that is the same quality as hasbro and takara stuff, and stuff that cant even stand up or stay together under it's own weight. What KOs were you wondering about?
It depends on the KO. I just got the Ratbat/Rumble set from A3U that is a Chinese KO and it is pretty damn good set.
http://www.tfw2005.com/boards/showthread.php?t=126551 Detailed comparisons (including quality) between the originals and a lot of the recent KOs.
that is a very vague question. it is like asking how complex are transformer toys? well duh it depends which one. for KO some of them are very good in detail. right down to the exact specification of hasbro/takara. my "Cassette Man" KO is very very good. just like the real thing. but as many KO are made of lesser quality materials its best to treat each one with kid gloves. KO can be very addicting. They are made in very small numbers compared to has/tak production. they are often retooled so they are unique, and due to their limited release they can be very rare.
So far, it seems , that, like, if they're like way bigger or , way smaller than the original then they're like pretty sturdy ya know, But when they're like the same size as the original then they're usually like cheap feeling. All my oversized and micro ko's feel cool, but my normal sized ko's are mostly crappitycrapcrap. Any ko larger than 4 inches that's sells for $2-5 are usually shiddy. Not speaking for all ko's , just the ones I own mostly