S12 is a great unit also ... my 2nd choice in this price segment as the B2 allows a future upgrade if you so choose in the future which can extend system life by 18-20 months. If it's not a Gaming box however, I recommend the S12-520. If ya have a windowed case, not being semi or hybrid modular makes some folks shy away. The newer model has a singe 40A 12v rail whereas the older model had two 20A rails and the warranty jumped from 3 to 5 years.