“Is it better to purchase SAT subject specific books by Barron’s, or the one that covers all subject by collegeboard?”
The collegeboard book contains real exam questions for each subject. I wouldn’t use it to study, but I used it as practice to get a sense of what the real exam will be like.
Barron’s tends to be harder than the actual exam, so if you have a lot of time then studying Barron’s will make you very prepared. Also, Barron’s is not always the best for Literature and Maths2
I actually used the Princeton Review books for Chemistry, Maths2 and Physics. I felt like it was the closest to the real exam and covers all the necessary topics. So if you’re low on time, it’s a good choice since you won’t be over studying.