it depends on which model you are looking at. most of damasko models looks similar in terms of design other than then the GMT and handwinding models.
if you notice the dials of some of the models, they are basically very similar and the hands as well. this result in that using a standard base dial and hands and change the color a little here and there, you get a new model.
if you prefer fuss free servicing, then damasko as most sinn models have argon gas which may needed to send to germany for service.
i would take a sinn over damasko for the following reasons
1) various designs and models
2) case - tegimented.