Although not a Tozer ‘fan’ per se, I would not label him as a mystic, although he does falsely appear that way a bit, in that he highly emphasised the Spirit and was also a poetic sort. A.W. Tozer is an interesting person to compare with the reformers. On one hand he was more like them than most who claim to be like them and on the other hand he certainly felt in some areas he had a better understanding then them, but so do many in one way or another.
What makes Tozer most different from reformers is simply that he did not believe in the cessation of those highly miraculous gifts of the Spirit, but rather urged that we should pray for them now. This does not make him a mystic it simply makes him a modern day charismatic. Among charismatics I would say Dr. Martin Lloyd-Jones and Tozer are among the best. From my memory of some of his audio sermons that fed me spiritually quite a bit as a young believer, I would say Tozer had a very clear sense of the cross and an in-depth knowledge of early church father theology as well as reformed theology and generally preached accordingly. I would say that Tozer was closer to Calvinistic in his view of the atonement rather than anything else.
Where I would criticize Tozer to some degree is where he personally found it most humorous. I remember him making fun of one of his critics by calling him a ‘spiritual perfectionists’ and as funny as it sounds I think this label fits to some degree. If you ever read Tozer and notice to what degree he expected a Christian to be sanctified and holy, inwardly truly following Christ, it is almost as though the Apostle Peter would have come way to short for him! Paul may have just made it! This is really what Tozer was about he was a unique charismatic holiness preacher. He seemed to be a man of prayer and very serious in his reverence for God’s word. He would have not approved of Christian rock music for example (something I like a lot). In some ways my criticism seems like a compliment and it is, but at some point it just starts to rub the wrong way and I do not think Tozer books on their own create a balanced diet. Tozer is possibly a good supplement to a balanced diet. One needs to put him in perspective during a generation that was influenced by the charismatic movement and holiness movements.
In the end, I still have to say I like Tozer as a person, he was so very genuine and honest. I would not place him among the ‘bad guys’ or ‘mystics’ but let him sit over with ‘the good guys’. I would not recommend his books on the Spirit (if you are Charismatic I would read Lloyd-Jones). I would highly recommend his book on the ‘Attributes of God’ as possibly the best on the subject. This is merely my opinion on having read several Tozer books and much more reformed books.
Maybe the best compliment I can give Tozer in how he was received by those most reformed is, by quoting J.I. Packer, who seems to like Tozer even more than I do:
“Through all of Tozer’s books and articles there shines a passion for God that puts our shallowness to shame. Reading him is like drinking at an oasis in the desert.” (J.I. Packer)