I've run in both the 12km event and the Half marathon at the Chevron Perth City to Surf event (in different years), and both have been great experiences.
The Event is the largest running event in the state (in number of participants) and hosts a 4km, 12km, half and full marathons.
It is a moderately hilly course, or quite hilly for road runners, but has a fantastic scenic course which takes in the swan river foreshore, kings park and ends at City beach.
The expo is quite a bit of fun and the race day is always beautiful. Its not a course where you will set a PB given its hilly nature, but it is challenging and there is always support on the course.

I highly recommend this race if you are a visitor to my city, it is a lot of fun and a great day.