Barleywine, I agree completely but for a beginner, reading not only one but two difficult texts to distill the difference - well,
I wouldn't have managed it.
I would recommend to read Rachel Pollack's 78 Degrees of Wisdom for the RWS, and DuQuette's book for the Thoth. Both give good introductions to the decks without dumbing them down, and you can get a good feeling where each deck stands.
The images alone already tell you the difference: RWS is a narrative deck, and you can read it by just looking at the pictures and finding a story in the cards. The Thoth is, at least in the minors, an abstract deck. You can read it by just looking at the shapes and colours, but you immediately feel that you need some background, some knowledge. It's more challenging to find the "story". The cards help you less.
That makes many people think the Thoth is less suitable for beginners. I think that's not true. Go with the deck that calls your name. Being challenged a bit more in the beginning is not a bad thing, and for some people, the narrative scenes in the RWS may even be an obstacle because their stories may overwhelm your own.
But don't read one deck with the meanings of the other. That may be possible but you simply miss out.
Read a lot with the deck and read a book along with it, and you'll see which deck speaks to you.