Pros: Outperforms other products detecting hard drive problems, has capabilities to isolate cable, memory and system bus problems.
Cons: It could look a little snazzier.
Scannerz for Mac OS X is a hard drive, SSD, and system test tool for Mac's. I got this tool over a year ago and it's just continued to get better as time progresses. The current version is 1.8, which implements both a much higher speed interface to accommodate some of the high bandwidth data rates in the new Mac Pro's and it also uses the new diagnostics mode which became available in version 1.7 of the product. Since all updates for the product have been free, this has been a great buy as far as test tools go.
I suspect many people think that this is a "discount" version of TechTool Pro or Drive Genius, but it isn't. The company's old web site used to emphasize the fact that instead of creating a tool with a wide variety of features that more or less cloned other company's products, they had decided to emphasize doing more sophisticated tests on a drive and system. In my opinion, they succeeded.
Scannerz can detect both bad and weak sectors, whereas other products can only detect bad sectors. Scannerz can also be put into a diagnostics mode to perform tests on cables, the system bus, and system memory. The manuals were overhauled with the release of version 1.7 and they now include step by step instructions for testing and detecting system problems. The product also comes with a file system events monitor, which can be either the fully featured and configurable product named FSE, or the simpler version named FSE-Lite.
As the product has grown, they've also added Performance Probe and Phoenix. Performance Probe is sort of like a high level version of Activity Monitor that summarizes CPU activity, memory use, I/O use, and drive space. Phoenix is SCSC's version of an e-drive, which is created right off an existing installation of the operating system. Phoenix can also do some basic volume cloning. I find Performance Probe's re-introduction of the memory pie chart now missing from Activity Monitor on Mavericks to be a real asset.
In testing, Scannerz simply out does the other tools on the market, period. I was able to find numerous problems with some old drives that some of the other products on the market missed all together or couldn't handle. The new diagnostics mode can perform more thorough tests on questionable regions of a hard drive or SSD, and also can test both internal and external cables as well as the system bus and memory.
The only problems I could see users having with this product would be if they have somewhat rare or obscure interfaces, like really, really old hard drives or some drives that use interfaces not normally supported by Mac's. Users should read the system requirements on the company's web page, but I had no problems with any normally connected SATA, IDE, or RAID units. I also used it on the components of a Fusion drive without any problems at all.