Thank you for the kind words! I tried to minimize the performance impact as much as possible.

It's true that the SGV icon doesn't look that good with a big number of tabs, but there is just not enough space. I have https://github.com/Loirooriol/tab-counter-plus/issues/13 about adding font customization, but it may be tricky since currently I change some styles depending on the length of the number.

I agree that excluding suspended tabs would be useful. Actually I already have a draft patch that lets you exclude suspended, hidden or pinned tabs. But first I would like to add some automated test coverage, and lately I haven't had much free time for this.