Ok - first, you'll have to just prepare yourself to spend $150-$200 for your meal. I'll give you a moment to process that....
Now that you've got your mind around that, let me tell you that if your budget allows, this will be some of the best food dollars you can spend (in DFW, at least).
I have always found the staff to be super friendly and accommodating. I even saw someone come in wearing jeans, ball caps, and crappy t-shirts and the staff was very kind in asking them to sit at the bar. (Which, by the way, they wouldn't even be allowed at all in most restaurants of this stature.)
The atmosphere is refined and laid back. The lighting is neither super dark (like Mortons) or overly bright. Once the place fills, the noise level is fairly high, but not so high that you can't have a good conversation. I love the wrought iron and brick decor. Also, you can see through to the private rooms - the whole effect is warm and inviting.
The wine list does have a few pricey items on it, but I've always been able to find a great .... not just good... shiraz on there for less than $50/btl.
I recommend a start of the Lone Star salad. Split it with someone if you can - there's plenty. It is a wonderful blend of greens - tasty and a bit bitter. The honey encrusted pecans and other accoutrements are exceptional.
The steaks are the very best! I always get the ribeye - 16 oz - (cooked medium rare) and sometimes get it a topper of bacon and blue cheese. Literally every bite is life-changingly delicious. The sides are great. I love the habenero corn and the mashed potatoes.
So... post meal is my only gripe. Their desserts are fine. Never had that "ah-ha" moment with the desserts here. On this visit, I had the chocolate melting cake. This is named similarly to the dessert found on Carnival cruises (I'm assuming no connection). Unfortunately, accepting that the ice cream at Old Hickory is a higher quality than the one on the cruise ship, the size and quality of the chocolate cake doesn't meet my standards. It was fine - but it wasn't mind-blowing.
So, if you possibly can, go here. It really is probably my favorite restaurant and if I could afford it, I'd be here more than for just special events/anniversaries/birthdays...