The good: RoadRunner warns you when you are approaching a speed camera. If you are in the vicinity of a speed camera, the app will go 'beep, beep' the way RoadRunner does as he passes Wile E. Coyote.
The bad: I'm guessing that for Singapore, the app relies on information from the Traffic Police. Unfortunately, our boys in blue (or in the case of the Traffic Police, our boys in white) have not actually revealed the exact location of these cameras (strange that). They only have a list of roads along which the cameras "may be deployed". These roads include long stretches such as Adam Road, the AYE, the BKE, the CTE and the ECP.
The ugly: This means that if you try to use this app as you drive down any of the 39 roads on the list, your iPhone will be going 'beep, beep' at you every few seconds. I tried this app out in a taxi and it beeped constantly as we drove down the PIE and then Adam Road. The beeping gets old very quickly.
In the features list, the developers also claim that you can set the proximity for the camera warning. A whole minute of fruitless jabbing all over my iPhone screen did not reveal a settings option. (However, according to the laws of the universe, I will discover the settings option in a very obvious place after I post this).
DVD bonus extras: It calculates your speed very quickly and also has a little compass that tells you what direction you're travelling in. (The compass seems generally accurate but I didn't put it beside a real compass to test.)
Rating: Save your US$0.99. This app is not very useful for roads in Singapore. It might be more useful in other territories (RoadRunner covers 33 countries) though.