Went here in the afternoon for late lunch. Place is slightly hard to find, so I called the restaurant and they literally gave me step by step instructions - so that is good service upfront.
Food: Since it was afternoon, there was a very good value tea set ($38!!), any choice of 3 mini-size burgers with wedges and comes with a choice of hot tea - so we ordered a Chicken Burger tea set. All other items was an extra 20% off, so I got a Portabello Cheeseburger for only $68.

Chicken burger was mini-sized but still quite ample for light lunch, considering it did come with wedges. Chicken was a thick fried battered piece, very juicy and piping hot. Came with mayo and lettuce tomato. Wedges were decent, very thick with potato. I'd definitely recommend this set for value.

Portabello Mushroom burger was delicious!

Came with a thick and flavorful portabello mushroom. The burger meat far exceeded my expectations and was much better quality than Shake 'Em Buns. The meat was much thicker, more juicy & tender, full of the quality beefy-ness, and came cooked perfectly - slightly pink in the center. The sesame bun was also a good pairing - just classic thick hamburger bun, the ones you get in the US. The burger was so huge, I could barely even take a full bite.
Service: Besides having the patience to give me good directions on the phone, service here was great. Very inviting! This place was a order at the counter place, but they had a waitress to deliver your food; take your orders if you dont want to bother going to counter; and give you condiments; clean up...etc.

Also, there were people who waited for a table (seating filled up fast!), and the waitress would go outside and check in with the customers.
Sizing it up: By far the best burger place I have been to as of yet in HK. Its just authentic and done right. I actually prefer this over Harlan's burgers (which have a slight high-end twist to it). The seating was limited but the seats are comfy and if there is a wait, definitely worth the wait. The food came piping hot (almost burned myself) and was made to order, so there will be a bit longer wait since its not a fast food burger joint. Drinks selection was very large with Beer, Wine, Snapples, Vitamin Water, and other specialty drinks. Also, the burger selection had a very good range, from the classics to very interesting ones that I'd like to try (Soft shell crab burger; Foie Gras burger, and a range of seafood burgers (scallop; black cod, etc.). Very very satisfying experience and two thumbs up!