While the outside isn't really much to look at (when we pulled-up, I was thinking 'no wonder we got such a great rate'), I would definitely stay at the Hotel des Bains next time I go to Gerardmer.
It's a straightforward, old-style hotel. However, our room was nicely decorated and thoroughly cleaned each day; there's a great combo-bar/lounge/café off the lobby with a free Internet connected-computer and widescreen TV (mainly used by kids); and the staff was incredibly friendly and helpful. I would recommend it for families, friends and couples alike.
It was fairly noisy during the morning and late-afternoon 'commutes' to/back from the slopes, but no more than for an hour or so at a time (and didn't really disturb my night's sleep).