This one is tough. I'll be visiting it soon, so more details are yet to come. I scoured the internet, only to find brief references to this place with no real info given. For now, I'll post a map and you can head over to check it out yourself.

I can tell you that via word-of-mouth, I hear this place is decent, and my boss goes there rather often since it's near our school. The building looks big, but I'm not sure how much is occupied by the sauna. Anyway, like I said - more to come soon :)
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So, I went there on Thursday evening. Had the place to myself, (save for a few old ladies and two other people in the jjimjilbang!) and just spent enough time to check it out. I'll be going back though.
The Sauna is basic. Basic basic. Just a couple warm tubs, an ice tub, a dry sauna room, and a lot of showers. I gather the main purpose of most peoples' visit is to scrub oneself. The distinctive feature is that the tubs themselves were built with beautiful, natural stones. Instead of enjoying them on the walls, you can feel them right under you.
The jjimjilbang is also basic, but really pretty as well. There is one central area with a TV and snack bar, the ice room (with a cute door like a walk-in freezer!) is on one corner, and the restaurant is in another corner. The segregated sleeping areas can be found lofted in the other corners, and along one wall of that main room is glass with a door. Through that door you'll find the warmer area: an anteroom with TV and 3 stunningly-tiled dome-ceilinged hot rooms.
Overall, it was small, but had such a nice look I'd love to visit again for the cozy feeling.

신촌사우나찜질방
대전 중구 문화1동 1-182
Daejeon, Jung Gu, Moonhwa Dong 1, Building 1-182
042-224-4545

Wikimap of Sinchon Sauna