I got one for RMB 20 for half a day (i arrived in the afternoon and was a bit short on time), so I told the guide I wanted to only visit 3 attractions in the afternoon.
Note: When you get the guide, you will need to register at a "tourism counter" near the ferry terminal. You pay directly at the counter.
Pros:
1. The guide will provide heaps of information on each of the sites visited (although I don't remember 99% of the things she said).
2. If you're short on time, the guide can find you 'short cuts' to your destination, walking along small alleys.
Cons:
The normal practice is that the guide will take you "Shopping" in between the stops. This way they earn a bit of commission from the shops.
I had to use the "time" pressure to get around this, as shopping wasn't on top of my list.
Most attractions closed around 4:30 - 5:30 pm (Dec 08).
