I feel they do teach some truth. But they, the Watchtower Society, will always use the truth as a hook to reel you in. Then they'll try to convince you, otherwise called "studying the Bible", to do what they teach and what do they exactly teach in most Study edition Watchtowers? To follow men. To follow the Governing Body and their lackeys, that is the District and Circuit overseers and the elders in every local congregation.
Would you allow God to tell you what to do? If it was written in the Bible that you had to do this or that?
Well, you may not want any person telling you what to do, but the studies are actually not Bible studies, they are Watchtower publication studies designed to influence your decisions based on scriptures they quote or reference out of the New World Translation with it's biased translation. They'll try to convince you that to do different from what they teach is to go against the Bible and against God.
So if you really have a love for God or the Bible, then read the Bible. Try to get a version that has a lot of notes like the Quest Bible, or the Holman study version, or use http://biblos.com and read it for yourself, don't just take what they say at face value, they are sincere people, many of them, but they are victims of mind control who have been trained to try anything to reel you in. So if you believe in God then try to get closer to Him through his Word and pray for Holy Spirit to help you understand. You don' need anyone to tell you what the Bible says if you are a Bible reader, right?
BTW I found Ray Franz's books, especially In Search of Christian Freedom to be a breath of fresh air compared to the stuffy study editions of the Watchtower. You can get a PDF online version of that book very cheap at http://www.commentarypress.com