I used both - undoubtedly Thom books are excellent reference pieces, but as a learning tool I think Pratt's books work a lot lot better.
If you are getting on fine with Thom, and passing exams, carry on. But if you find yourself struggling, Pratt's books can be a revelation. They are written in a much more accessible style, with the odd touch of humour to lighten up what can be very dry stuff, and they do not attempt to cover material that is out of scope for the PPL.