First, I carefully read through the code in the entire XPI, looking for any funny business. (just unzip it and see for yourself). Since this plugin (along with a million others) can see all of your data on all of your websites, you should definitely consider doing that sometimes. You should also consider having multiple browser profiles configured (see FF Profile Manager) for different levels of security.. you probably don't need Ad Blocking on your bank's website!)
Second, I installed it. And, wow. This is fantastic. Simply does what it says, with an extremely configurable (and relatively easy-to-use, given the complexity it's hiding) scrolling behavior UI. Of course, you don't even need to tweak it -- it's got presets for most needs. Want to scroll fast or slow? It's got you covered.
But, most importantly, it just works -- smoothly and cleanly. Combined with Firefox's Reader View, this is as nice to read on (or nicer) than a Kindle Fire e-reader (at least if you have a decent screen.) No more page flipping needed.
Absolutely thrilled - love this plugin. Excellent work. A long list of contributors (and translators) means that it's truly a community project. I don't know what the other reviewer was referring to by license issues, but the BSD 2-clause is just about the cleanest, most open license in existence, trumping even MIT.
I'm currently in the process of switching from Chrome (ium) back to FF after many years away. I'll still do certain types of development on Chrome, but FF is so much more appealing (and more configurable). This plugin is awesome and really helps me move in that direction faster.