When comparing GrandPerspective vs WhatSizeMac, the Slant community recommends GrandPerspective for most people. In the question“What are the best disk space analyzers for Mac OS X?” GrandPerspective is ranked 4th while WhatSizeMac is ranked 9th. The most important reason people chose GrandPerspective is:
GrandPerspective has been released as Open Source under the GNU General Public License.
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 Updates information in real-time
WhatSizeMac is able to listen for file system events and update itself in real time. So it never needs a full volume measure but once in a very while.
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 Poor tech support
No update for Mojave.
Con Commercial
WhatSizeMac cost $29.99 and there is a free trail available.