I like the tabs being on the left side of the page and vertical not horizontal and on the top of the page. However, there are two things that bugged me enough to uninstall this.
1. Tabs still appear at the top of the page, so now you have tabs in two locations. That bothered me a lot.
2. In the compact mode of the tabs, I wanted the width of the tabs to be shorter so that I could see more of the page. I was able to adjust to width of the column shorter than the default but I wanted to go further than the limit to make it just a half inch column on the side of the page. As it is, it takes up too much visual space for me to appreciate it.