Everything Button Guy has created has worked no problem for me. The only missing detail is perhaps having the ability to change the icons, or perhaps have a simple few icon sets.
Ideally, to have something like, "The Button Guy Suite" that encompassed everything he's created with an options page featuring the ability to turn things on/off, reskin the icons to a couple themes, hotkey/macro/magic, toaster oven, etc.
I don't want to add Keyboard shortcuts yet, not until Firefox adds some way to make them customisable (they are working on it). Other wise there is no way to turn them off for people that don't want it, or change it to avoid conflicts.