There is a new version available and though I was disappointed upon its initial release, they seem to have the bugs worked out and it is much more stable.
The multiple window view is really slick - especially if you have an ultra high resolution monitor like a 4K display. It allows you to make changes to your css and see instant results among your breakpoints.
I have now been using this software for nearly 3 years and while I can say it is still the best way to work quickly on CSS files, it is proving to be falling short in some of the important ways I have found my self producing my websites.
This software doesn't like Bootstrap very much. - it throws errors on it and the cleanser is very little help.
Skybound Stylizer is a CSS editing program that I have been using for many years now and it is a great peice of software. It has the ability to perform on the fly CSS file adjustments either point and click or type code and has multiple browser rendering built in. At current time is supports multiple versions of Internet Explorer, Firefox and Google Chrome.
This program is very easy to use and offers the ability of working local or directly on your server. Once finished with your css adjustments, you can either save local or to your server. Many of the adjustments can be made with sliders and you also always have the option of manually typing in your values. Skybound keeps it updated and does so from within the program.
I definatelly rank this as the BEST CSS EDITOR on the market today.
Visit them and have a look for your self - they offer a free download.