It really depends who you read, what you read, and what you want to get out of the Thoth. If you read intuitively, i.e., by using the images alone, then it doesn't really matter what deck you use; you can read any. However, if you go by the traditional meanings, and the ways they are expressed, then the RWS and the Thoth aren't that different, even though they may look radically so. However, the Thoth lends itself far better to advanced study, and that is what I would recommend to anyone studying it. Not to learn meanings by heart, but to learn why those meanings are what they are.