Should I upgrade to Mojave?

[MSastre]

Personally, I had less trouble with High Sierra on HFS+ than Mojave on APFS. (random kernel panics after wake up from sleep which forced me to reformat my SSD already twice in three months). High Sierra 10.13.6 is rock solid and much better than Sierra. Fingers crossed that the last update of Mojave will solve the annoying bugs.

Personally not having any problems with APFS on any of my machines, but I made sure to do "clean installs" when switching over to the new file system.

 

[maverick28]

Good thinking. I have external SSD that have EC, Sierra, HS and Mojave on them and the internal Fusion Drive still have Mountain Lion on it. Believe it or not, ML runs the iMac faster and smoother than any of the others. But then Safari and Chrome are just unusable. Just for fun I DL Waterfox and it does a very very fine job on Mountain Lion. Just to say that if n OS runs so fine on a machine, there may be no reason to rush to an upgrade. BTW, Mojave on an external SSD is the solution for me and it runs pretty fine.

I run OSes indicated in my signature: Lion and Mavericks both surpass High Sierra in terms of performance and smoothness, despite the latter being better and faster in some aspects (by the margin of error). However, considering Mojave it's not performance that troubles me but the fact that Messages no longer supports the Google Hangouts account which leaves off-board many people that don't use Macs. This is outrageous.
As for a browser. Up until now I used Chrome 49 and Waterfox (the latter still supports Lion and Mountain Lion), and hold the old unsupported Chrome the champion of performance for 10.7.5 comparing with the standard compliant but slow Waterfox . However, miracles do occur from time to time, and here's the one: Firefox "Quantum" (ver. 67) was ported to run on Lion and Mountain Lion by the name of "Firefox Legacy" based on FF 67. The performance and speed simply rocks and is on par with the most up-to-date versions of the genuine builds available for newer macOSes.

Download Firefox Legacy here:
https://parrotgeek.com/fxlegacy.html

 

[Mac Hammer Fan]

Personally not having any problems with APFS on any of my machines, but I made sure to do "clean installs" when switching over to the new file system.

Not necessary to do a clean install. After the supplemental update of 10.14.6 the problems are solved.