Arima Onsen vs Sake Brewery

If I only have less than half a day in Kobe, should I visit Arima Onsen or sake brewery district? I am interested in both, but I wonder which one is a richer and more quality experience for first time visitor to Kobe.

Will you have a chance to experience onsen elsewhere while you are in Japan? In my opinion, Arima would require more time, and with the lengthy access it would seem a bit too rushed if you only have less than half a day.
Why not combine the sake district with something closer to downtown Kobe? E.g. the foreign houses quarter (Ijinkan) between the Shin-Kobe and Sannomiya stations, the Chinese quarter, or a walk along the seaside promenade.
The brewery I went to (Hakutsuru, but I suspect the others are similar) had a well done museum on sake history and production, with some free tasting at the end, but do not expect to be able to see the actual production process.