Was Lord Voldemort an evil genius?

I just finished reading the Harry Potter series for the fourth or fifth time, and I found it to be exceptional. I was curious to know what everyone else thought about Lord Voldemort and his intelligence and manipulative and cunning ways. Some people who I have asked have said, I quote, "he made so many blunders, and is a bad excuse for a villain". I, however, thought the blunders were only due to his arrogance and lack of understanding of human emotions and reactions, which is a common trait in evil genius, supervillain types of arch-enemies. I for one thought he was absolutely brilliant, he was sadistic, creative, and, in my opinion, an excellent liar, for he truly tricked all of the people who surrounded him in different ways, whether it be his own death eaters, or his peers or teachers. With the exception of Dumbledore.