I tested Version 3.0.21 (Last Updated: June 22, 2017)
on Firefox 54.0.1 (32 bit) on Windows 8 with 3.5 GB memory.
It installs Ok.
The first page I tested it on was 4chan's Comic and cartoon catalog, not particularly large with small thumbnails.

Problem 1: the addon slowly scrolls down the web page to complete its capture
Problem 2: the browser locked up for a good 5 minutes while the addon was (I guess) composing an editable screencapture in a new tab.
Problem 3: I noticed data was being downloaded from a third party website. Why? Will this work offline like other page savers?
Problem 4: once the capture was complete the cursor changes to a kind of paintbrush and the browser ran very slowly.
Memory use reached 3.5 GB.
I had to control-alt-delete for two minutes to regain my task manager and then able to close the Firefox tab with the editable capture. Browser and computer return to noemal operation.

Clearly something needs fixing here.
Pearl Crescent Page Saver does not do this, it just captures the whole web page and saves it in a file.
I use Pearly Crescent in my other Firefox profiles with no problem.
Pearl Crescent Page Saver does require a restart however, which is why I tried this "Awesome" one.

This might work for some people, but such an initial experience is enough for me to swear never again.

great

This add-on does not capture the selected area, but results in an enormous horizontal shift.

This addon is corrupted

very useful lately since my printer is DEAD!

OK

Awesome ScreenShot Plus a perfect add-on with my Mozillla FireFox browser. Five plus stars all the way

great!!!!!!!!!!!!!!!!!!!!!!!!!!!

DOES EVERYTHING IT CLAIMS; THE EDITING IS AWESOME AND EASY; BEST SCREEN SHOT ADD-ON I'VE TRIED.

MUITO BOM

Not working in andoird version

This well-designed app does exactly what it's supposed to do, and doesn't override other functions.

screen shots are perfect and the annotation tools are easy and intuitive

highly recommended

Installed, rebooted Firefox 54. Tried to capture. It sits there indicating it is capturing. Nothing happens. Perhaps I need to create an account, but I don't want to. Uninstalled.

I tested 5 app's for screen-shots - that one is the best :D

very valuable