I've been to both too and have been meaning to respond to this. They are really very different restaurants, both with their merits.
I agree with boynamedsous' positive comments on FDS. I've had a few wonderful meals there. I would disagree on the assessment of Bear, however. While I wouldn't give it across the board glowing reviews, I think "all sizzle and no steak" doesn't represent my experience. My meal and Bear had highs and lows - the highs were very high, and the lows were more just places where things weren't as good as I had hoped. Bear is ambitious and I think that when a restaurant is ambitious, it can fall short of what it sets up. I think it just depends on what you are looking for in a meal. FDS is more consistent, but it's probably less adventurous. Sometimes I'm willing to take a few mis-steps for the sake of adventure. I definitely plan to return to Bear, and I've already been back to FDS.
Outside of the food, one thing that I think is important to note in comparison of these two places is how different they are atmospherically. FDS is set up in an historic house - the restaurant occupies the front rooms of the ground floor. It is open, and bright compared to Bear, which has more of a modern feel (on the ground floor of a recently built condo building), with dimmed lighting and more clubby music. Both have excellent service in my recollection: FDS more personal, but Bear very professional.