Easy to put together.  Base is wide enough to hold the components in a sturdy way, except for the very top tray, which wobbles a tiny bit.  But no problem - we have put the back of it up against another piece of furniture and our small cat loves to sleep on it.  Not sure it would work for a large cat so well.  It comes with a "replacement" ball and string, which is nice.  Have not noticed any "shedding" of the faux fur material.  I was concerned about that and the "wobbly" factor after reading comments on other products.  I feel we got our money's worth definitely!