Hi viki00762, I'd say if you're starting out the best place to go first is the OG. I haven't gone through all the different books from all the test prep companies but the topic has been discussed in many different ways on this forum. I'd say the bottom line is that each of them is good and the difference will lie in how you learn and what your target score is.
Obviously I can vouch for the Veritas books, and the common consensus on this forum is that the
MGMAT books are an excellent resource as well. I've never heard anyone complain about Kaplan books either, so it's certainly not a bad idea to check those out.
If you're just starting though, the OG is the best place to go, and then you can compliment it with various other books and courses offered by the different test prep companies to help you maximize your score.
Best of luck and please let me know if you have any other questions!
-Ron