When comparing GrandPerspective vs DaisyDisk, the Slant community recommends DaisyDisk for most people. In the question“What are the best disk space analyzers for Mac OS X?” DaisyDisk is ranked 1st while GrandPerspective is ranked 4th. The most important reason people chose DaisyDisk is:
While working on your Mac you create and download a lot of files, but rarely delete anything. As time goes by you have less and less room for your data. DaisyDisk finds those hidden unused gigabytes.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free & open source
GrandPerspective has been released as Open Source under the GNU General Public License.
Pro Small size and fast
Pro Helps find and delete files taking up HDD space
While working on your Mac you create and download a lot of files, but rarely delete anything. As time goes by you have less and less room for your data. DaisyDisk finds those hidden unused gigabytes.
Pro Awesome visualization of files on drive
DaisyDisk gives you a perfect overview of all the disks connected to your Mac, be it Macintosh HD, flash card, Thunderbolt disk or network storage. And does it in a beautiful way.
Cons
Con App store version costs $1.99
GrandPerspective costs $1.99 on the Mac App Store, but it can be downloaded for free from Sourceforge.
Con Calculation based on 1000 not 1024
It's nice to have a base 1000 (MB, GB, …) calculation but it should be optional. Default should be 1024 (MiB, GiB, …)