Just get Chat GPT 4. I've made this mistake for a couple months. Chat GPT 4 can do so much more, and it can read PDFs much more efficiently. Do not buy the premium of ChatPDF. ChatPDF would have to significantly lower their prices for it to be worth it, as it is the same price as Chat GPT 4 - a much more versaitle and helpful subscription. However, you can use the free version very limitedly, which is somewhat convenient if you do not want to pay for Chat GPT 4.
It is good and very fast, however sometimes, it makes an answer by itself with no relationship with PDF. Also, we can not combine multiple PDF together which is an greater option available with lots of similar app. I guess not able to combine multiple pdf for single chat is the biggest limitation of the ChatPDF.
