I am a new mac user also but have been using ccleaner for years with windows. Along with VGA free it was all I ever needed. CC was working fine for a long time on my mac till one day it just stalled wouldn't do squat. I tried the check by check method and found two places that were hanging. First one was trash, second was chrome cookies. Also after going check by check I got the "oh snap" from Chrome and Safari got stuck in a loop of crashing and trying to re-open. A reboot solved that and all seems to be working fine now. I'm a little scared to try and wipe the free space.
iMac Model Identifier: iMac8,1
Processor Name: Intel Core 2 Duo
Processor Speed: 3.06 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 6 MB
Memory: 4 GB
Bus Speed: 1.07 GHz
Boot ROM Version: IM81.00C1.B00
SMC Version (system): 1.30f1