It should also be noted that they both have:
The Horror Megapack
Kindle &
Nook
The Mystery Megapack
Kindle &
Nook
The Adventure Megapack
Kindle &
Nook
The Ghost Story Megapack
Kindle &
Nook
The Western Megapack
Kindle &
Nook
The Military Megapack
Kindle &
Nook
All of them are $0.99 as well.