almost magnificent. but ... Rated 5 out of 5 stars

Mouse-only zoom & reset
< : 3
much better than FF default which needs keyboar and mouse.
~(((())))Q ....... < : 3

A joy to use. Thanks.

However, some things a bit odd.

~ I have never grasped the perverse idea of moving a scroll bar downward to move the page up. In the same way, when I 'pull' the mousewheel, why is the default to move the document 'away' ? (Make it smaller, as Desargues might say. That's my perspective on it, anyway.).
So, I was pleased to see the 'invert scroll wheel direction' option.
Ah, but it only changes direction in a text area ! Pics still behave the 'wrong' way.
So you get two different standards on the same page. To anyone but a programmer, this is bizarre.

~ When you zoom the page, the scroll bars change size as well. That's unexpected, too.

~ There's an apparent limit of 300% zoom. Maybe enough for most, you might say, by why the limit? Couldn't one do, say, 12% per wheel-spoke?
Yes, the rendering could get out of hand, but that's up to user, surely?

~ And if you do change the zoom steps, is it really so difficult to wait until the next time the user wants to restart? (Thanks for the polite warning , at least.)

~ An option allows you to set the 'OSD transparency'. Which would be wery good, if is wasn't for the persistently opaque border around the magnification, rather negating the feature. But at least I can switch it off.
I googled 'OSD'. I still have no idea what it means in this context. ¿-) Obscure Setting Description?

~ Hide/show toolbars? I can use F11.

~ I like the option to have the % on ths status bar, and the hover-reminder of how the feature works is welcome (though perhaps should persist until one moves the cursor away ).
It would be nice if it said 'MouseZoom 0.4.6', just so we know.

~ However, statusbar space is at a premium,
so I'd rather not have the icon (strange looking mouse, anyway..), but just the %age magnification.
In fact, at 100%, it could just be [%] , [.^.], & only wake up when it's different.

+ Wish-list:
1) fit image to screen
2) but only enlarge a small image to limit of visibility, using smart rendering.
3) centre pic zoom where cursor is, rather than top left of pic.

This review is for a previous version of the add-on (0.4.6).