I've been there a few times. It is rather on the expensive side, compared to places like Outback and Texas Roadhouse. Also, when you order a steak, that's all that comes with the dish. The steak. All sides are a la carte. However, the side dishes are pretty large, and are big enough to share, if you just want to order one or two.
I think their steaks are really good. They were also serving venison chops when I was there. You are definitely paying for quality, but the food is worth it, especially for a special occasion. But be prepared to shell out a few $$, but you can't put a price on treating someone you love!
As far as dress goes, you would fit in better wearing something nice, although I did see people in jeans and T-shirts whenever I've been there. But since it's a special occasion, I'm sure you would want to dress up a little anyway.