One thing I was instantly impressed by was his use of the color purple. Purple is one of those colors that is a little fickle. At times it looks strange - almost childish and toy-like - but at other times and in the hands of an accomplished painter who understands the way the purple behaves, it can have an astounding effect by adding visual interest. It rides the line between warm and cold while adding depth and sometimes soft fleshiness to the subject.
What I like most about Yoshi's work is that it clearly has his stamp on it. He has his own style.
Go click through his blog. He's got some great 40k, Fantasy, Rackham and Infinity models going back the past year or so.