When you use the module or plugin's Center style css with firefox it adds 3-4 extra pixels of space to the bottom of the module. If you care about what your site looks like cross-browser this is not good. I only gave it a fair because of this lack of cross-browser friendlyness. If you want to post up on thier forum it appears you have to pay so I dont think this qualifies as non-commercial either.
Thank you for great review!!! :)
It is open source and you are able to edit CSS styles easily. You will find them in style.css in the folder of the extension.
The Members site is for premium services, but you can publish absolutely free issues, ideas, questions on GitHub.
I have written that on the page of the extension, describing ways to get support :)