Check out this site
http://scholar.lib.vt.edu/ejournals/JAR ... -greer.htm
Love'm, hate'm or indifferent
I grow both Kurume and Satsuki. Kurume easy to find, Satsuki difficult to find. The differences that I have found are, Kurume are hardier. The flowers stay the same year in and year out. If it was red when you bought it, it will still be red in 20 years. The Satsuki flower for which they are prized, can have many variation on the same plant. One plant can display solid red flowers, stripped flowers, and solid white flowers. They can also have different flower petals on the one plant from a full flower cup shaped to the next twig being a shredded flower. Again not all Satsuki do this some stay true to one colour. Various flower petals too, doubles, single ruffled, small, medium, large. Also there are variation to the leaf small oval, long thin but always tending to be smaller leaf to other Aaleas. Basically like all Azaleas they are brittle and working with them can be frustrating. There is no warning when wiring just snap! Satsuki even more so because they are even spindlier than the Kurume. Best to wire new growth for this reason.
A lot of Bonsai enthusiasts don't like them, as most are not styled to "True" bonsai style. It's the flowers folks and the joy they bring to those of us who like flowering bonsai. I have a Satsuki that for the last ten years has been red and white stripped. This year however, it has produced solid red along with red flowers with a white throat along with the usual red and white strips. As for how to tell them apart, I have had an expert tell me that a Satsuki I have is a Kurume. After a lot of anal researching. I found it is not a Kurume it is infact a Satsuki. Be it rare, still a Satsuki. So some people can tell, some people think they can tell, I can't tell. So the long and short if you dont want to be anal about it, its an Azalea with some quirks that a lot of people happen to like. Some will tell you the difference is the little hairs all grow East or West

I forget which
I just know the so n so's can be very unforgiving. You can nuture a branch for years getting it just right and the dog just has to look at it sideways and its gone!
So love'm or hate'm its an Azalea and it gets all the pests and deseases that come with owning an Azalea no mystery.
Cheers
Great oaks from little acorns grow.