I too have been using this app for almost two years and it's great. I do think that the default settings may not be the best ones. I only use the Vertical 2 finger scroll and Two-finger click for a Right Mouse Button.

Here is the settings that work best for me; with a little tinkering one can find the right settings.

Vertical scrolling Sensitivity: Highest
Speed: Fastest
Ignore weaker axis is checked
Scroll resolution: second tick mark from Low
Maximum event rate: Highest

On the developer's website, there is more information about specific settings in Firefox's config panel which can be adjusted for better browsing using the iscroll2.

Also, it's recommended that "Use smooth scrolling" is turned off in the Apple "Appearance" system preferences if using iscroll2.