The truffle fries are great and come in a very generous serving. While I prefer the truffle fries at PS Cafe, this works very well as a side-dish as opposed to the main attraction. The cheese fries are also very good.
A split soup base (2 types, one on each side) is definitely recommended. I personally love the Sichuan 'Ma La' spicy soup accompanied by the non-spicy Tomato soup.
The meat at HaiDiLao is very good, though I won't recommend the most expensive wagyu dish ($52 a plate or so) as the others are good enough and it isn't worth the price.
There is a special 'HaiDiLao' sauce that the servers will make for you on request (they will add in some soup so it is a lot more liquid than the photo). I recommend it if you're unsure of making your own sauce, or just want to try it out. Nice with fish
The lamb rack came highly recommended and was indeed delicious, though for the price I'd suggest loading up on yakitori instead and maybe just getting one of these.