There are definitely a variety of woods that HI uses, but from what I have gathered, they are all about the same (high) quality.
The rhododendron wood being used on the KLVUKs lately is beautiful in person, very light in color and a hard wood. I've read the Lali Gurash is one of the harder and prettier varieties of rhododendron too.
Dhar wood is also common, which can be anywhere from yellow to red in color, and is quite easy on the eyes. I requested dhar wood for the handle of a custom kitchen knife being made right now.
And then there's satisal wood, which I have gathered to be more of a family of wood than one specific species of tree. Some is dark, some is light, some is red and some yellow, but all very high quality.
There are other handle materials used by HIMALAYAN, but less commonly including bone and antler, probably others too.
I personally like light woods, and the red woods, doesn't matter what they are. The pic I posted of my Foxy Folly shows one of my favorite wood handles that I own, and my Micro Bowie is also at the top of my list for its handles. Hope that helps!