My experience with DAT bootcamp was pretty dead on to that of the actual DAT.
What I was scoring across every subject (PAT, RC, OC, GC, Bio, QR), averaged across all five DATBC practice exams, was exactly how I performed on the actual DAT.
Keep in mind that the DAT Bootcamp practice exams are recycled questions from the actual practice subject tests on its website but I noticed an improvement after reviewing my answers and areas I was weak in for all the sciences.
Bio, however, is a little difficult to gauge, just because of how much information you need to study and a lot of that time can be spent studying in other subject areas you're weaker in.
I honestly did not spend too much time in Bio, other than memorizing the taxonomy groups for Kingdom, Phylum, and some of the Class and other areas for anatomy/organ functions, etc.
Also, Arie's study DAT guide calendar was very helpful. He recommends supplementing DAT Destroyer (bio, OC, GC, and QR subjects) w/ DAT bootcamp.
My experience with DAT Destroyer was only helpful in reviewing OC, GC, and QR. *Best add'n resources when it comes to practicing for DAT. Go through these books once and then once more again to solidify what you know (as suggested on Arie's study guide). They're a bit pricey and do some shopping for these books.
Not so much with Bio b/c questions started to get bizarre and seemed side-tracked from what I thought I really needed to know.