I've got an MSD Digital 6, and have had not problems other than you cannot use a gear-reduction mini-starter with this device. The mini-starter will not turn fast enough to generate a reliable signal from that unit.
Otherwise, the unit has a nuimber of great features....retards timing at start-up, two stage rev-limiter (all digital, done by rotating a dial on the unit) and a host of other things I'm unlikely to ever use. Overkill for the street? Sure, but the bright red anodized case looks really cool if you just happen to have you head in the passenger's footwell.
