I have the first one, the "old" edition, though the information is still fantastic. I have the two "old" versions for units one and two, and the new editions for units three and four.
They're all very useful textbooks, but I also have the CGP Edexcel AS-Level guide to supplement the first two unit books.
How is your revision going? I'm doing all four units in May and June, so I am pretty much 24/7 Geography right now. Feel free to send me a PM if you want to chat!