The only bad thing about Gaucho is how long the line can get. I've only been there a couple times because I never have time to wait in the huge line, but it would probably be worth it. The food is absolutely amazing. There aren't a ton of tables, but they seat you after you order so at least you'll know you have a place. Then they bring the food out to you too.
The sandwiches are all awesome. I love the Carne where you get to pick which cut of steak you want on your sandwich and it's paired with chimichurri, peppers and onions on delicious bread. It really holds up to the sandwich. I got NY Strip this most recent trip, but want to try them all. It was just a perfect sandwich. Depending on the sandwich you get, you'll be able to try some of their sauces. I loved the chimichurri that came with this, but also want to try one of the sandwiches where I can add my own sauce.
The roasted potato side is delicious. Also really good is the mushroom side. I'd trust any of their food. The alfajores are delicious and a great finish to your meal...if you even have room after all of the tasty food. We were told they were good with coffee, but chose not to get any this trip. I'll have to try it next time since I definitely plan to go back.