Ok. So I'll still come here if I'm craving, but only because it's the only one in the area. That said, the items aren't bad, so that's a plus. But comparably, there are much better options in this category.
Service however is very slow at times. You're left standing in line for a good long time usually. Perhaps it's the language barrier.

In Rundle Mall!
It's pretty authentic and their dishes are all quite traditional.
I would come here in a pinch if I was craving.
Being I think the only yum cha establishment in the mall, it's definitely on a winner. But to be as good as they are is an achievement

Bringing the Yum Cha experience to Rundle Mall, expect not really because you don't get the little trolleys and the tea and the hectic running around of all the Chinese staff. But you can order a serving of dim sim or two to enjoy the flavours at least.
This place is a bit pricer because it's the only one around of its kind, hence they can charge a premium for very average food.
Would I come here? No. But if I was craving Yum Cha and had no other option, I might just suck it up and get something small.

Approximate cost: $above avg