As to the banebots vs. Window motors, we've actually used both to steer our swerves (windows in 2010, Banebots in 2011). We had a few problems with both, but the Banebots definitely served us better.
With the
Window motors, running 1 per wheel module (#35 chain, 15T to 15T), we suffered from their
incompatibility with Jags until we
removed the locking pins. If you do this from the start (and personally, I'd avoid Jags unless you're CANing), you might be fine.
With the Banebots (RS-540s, 256:1 planetary gearbox), we never had a problem with the motor, but the gearboxes loosened up sometimes. This was likely simply a product of our mounting, since we stole 2 of the attachment points to mount it to the pivot. Great motors, but it's hard to give them up to the drivetrain in some cases.