BIO: This section is really random so it is hard to tell which one is more difficult. But the questions are really straight up facts so it's good to have lot of resources.
OC: very similar. The wordings of the DAT are really similar to boot camp. I did score higher on actual DAT though.
GC: Same as OC. It is very similar. Bootcamp is perfect for both OC and GC.
RC: I found this section on actual DAT a lot harder than it was on bootcamp. I ran out of time on my real DAT but I think that's because English is my second language. Or I just suck at reading, haha.
PA: I thought this section was straight copy from bootcamp since it was really, really similar. Make sure you try the generators on bootcamp. It helped me a lot! CDP helped me on angle ranking and hole punching but pattern folding and key holes are lot harder in the real DAT and bootcamp is the real deal.
QR: I found bootcamp harder than the actual DAT. The wordings are very similar!
I highly recommend you to get bootcamp. I used the bootcamp for one week before DAT, and I can definitely say that bootcamp helped me so much! Good luck on your DAT!