One of the most attractive features of B-Band pickups is the easy setup: There's no soldering or wire stripping of any kind. B-Band's under-saddle and soundboard transducers all use the same proprietary connector to plug easily into any B-Band preamp. This does mean that every B-Band pickup requires a B-Band preamp, but given how inexpensive these combos are, this ends up being a very attractive solution.
The A5 is a single-source sidemount preamp, with more features than the A3T (it also requires a full cutout of the side of the guitar). It features 4 bands of sliding EQ control and a master volume, plus the all-important phase switch, and—rare among onboard preamps—a parametric notch filter (you can control frequency and depth).