Well I heard about chads videos towards the end of my studying for the DAT but i did watch a few and I really liked them, especially when I was tired of reading and teaching myself. I am not sure how helpful they are for the actual test though because i didnt watch more than 2...
I took the kaplan course but i mean it wasnt really that helpful. I personally really like the kaplan blue book and I read the whole thing and basically for bio orgo and gen chem i re wrote everything into my own notebooks. (one for each science) on bio i left out like the last chapters (ecology and evolution stuff) and just memorized that thourgh practice problems . It helped me alot because I would highlight and underline and re writing really helps me remember things much easier. I used crack dat pat for PAT and it was great. For practice problems I bought the DAT destroyer book, its basically a whole bunch of problems and it is a GREAT book. Definetly worth the money. Ive heard the DAT destroyer QR book is really great for QR also.
Good luck!!