Zildjian K/Z hi hats are some of the best.  They are very common, but I still feel like the K/Z combo produces a certain unique characteristic that I am always pleasantly surprised to hear.  I have never owned a pair because I always had a set of K mastersounds which suit my needs.  However, if I had to go back and get new hi hats, these would definitely be a contender.  I have never met a drummer familar with K/Z's who didn't consider them to be at the top.

The mix of the K top and Z bottom produces qualities of both, but it still sounds mostly like a K (which is probably a good thing).  The stick definition is definitely dark and smokey like a K, though the chick sounds significantly different to me.  It is louder, and a bit brighter then the K's I have played.  When playing quickly or busily on the top, the sound atriculates exceptionally well and it feels very responsive.  I have only ever played the 13'' hats, but I am sure the 14''s are just as good if not better.  The wash on these is also exceptional, again retaining mostly K characteristics but sounding a bit brighter and more cutting.  The cymbals that these remind me of most are the A mastersounds, though these are definitely a superior cymbal pair.

There is nothing negative I can say about these cymbals.  They are amazingly versatile, durable, and good looking.  Even though they are bought together, it is still sort of cool to have a mixed hi hat pair like so many great players did in the past (Steve Gadd, for instance).  Many cymbals are matched, so this is a drawback buying 2 single hi hats presents.  Unless you have the time and resources to test dozens of combinations, these cymbals give you the versatility and uniqueness of a mixed pair of cymbals without the hassle of making them sound right.  These hats are perfect for almost any kind of music, and aren't that expensive considering the value.