Both apps show top 5 CPU processes. However, iStatistica Pro’s dropdown includes GPU process usage (which process is using the GPU) and Disk Write Bytes per process . If your SSD is thrashing, iStatistica Pro tells you which app is writing (e.g., Dropbox writing 500MB). iStat Menus tells you disk is busy, but not by whom without opening Activity Monitor.

If you buy iStat Menus, you should purchase it directly from Bjango's website rather than the App Store, as it enables advanced features like fan control and some sensor readings that are restricted by App Store policies. To help you choose, tell me:

is better suited for users who prefer a dashboard-style interface or require remote monitoring capabilities Quick Comparison Table iStat Menus - Bjango

The ability to see where your Mac is phoning home (the GeoIP map) is a security tool, not just a monitoring tool. No other menu bar app offers that.

The primary difference lies in how you interact with the data.