The description makes claims that are not so true in the current FF environments (other unloaders don't actually unload) that are easily verified in about:performance and about:memory. Checking those, one can see if the other unloaders work or not.

Annoyingly it does something no other unloader I have tried so far does, marks every tab it unloads as 'updated' in the same way as if the tab had an autorefresh or notification. This makes every tab it unloads look as though a message is pending if you highlight such in any way. UNLOADING SHOULD NOT MARK A TAB AS UPDATED!

Last it misses tabs that based on the setting should most definitely be unloaded. Sometimes even duplicates of the same tab (thus confirming no rule conflicts as it unloads some but not other duplicate identical content tabs).