I studied a 2nd year microeconomics unit at uni and the attitude with the staff seemed to be that this was THE book to use and had been around for quite a long time. Frankly, Varian does do an OK job with explaining different concepts, especially when he uses examples. The workbook really is quite ingenious as it takes what you learnt from the book and brings your knowledge of the content to the limit when you try to apply them to the questions.
I would've given this book 5 stars if it had come with the workbook but I'm afraid it's just not good enough on its own merits in my opinion. Varian also seems really really enthusiastic in the text and that enthusiasm can get really quite annoying when you see it so much. He interestingly enough doesn't seem to conform to economic dogma either with his treatment of certain topics, the compensating functions in particular. He calls the Hicks, "Slutsky" & the Slutsky, "Hicks". He places much emphasis on the former when the norm is to concentrate on the latter.
So excluding those things, not a bad textbook overall.