I rely heavily on taskbar features so ExplorerPatcher has been my savior and the only way I stil have Win11 installed on that machine. It was a little rough in the early days but it's gotten much more reliable, especially if you're not taking bleeding edge Win11 Insider builds from Microsoft.
Taking another look at StartIsBack I'm somewhat surprised that I preferred donating to ExplorerPatched over buying StartIsBack, I guess I didn't want to get used to something that I could not install on any new computer encounter without money getting involved. That, and the massive Google results dominance StartIsBack enjoyed while I was desperately looking for an 11-fix: at a certain level of SEO success the trust heuristics in my brain start screaming "scam" no matter what. In an objective level I really don't believe that StartIsBack is anything close to malware (doesn't even require admin, apparently (1)), but the SEO success and intense layman appeal of the site triggers all my fight or flight reflexes. Far too reminiscent of those old system cleaner tool traps.
((1) not that "no admin" would be a panacea: that might have been a difference back in the day when "taking over the system" was the only thing to really be concerned about, but these days on a typical personal computer there's plenty of valuable identity stuff that a piece of malware could harvest without ever escalating beyond user)
Its portable and gives your taskbar look of Windows 98 -> Vista.
I find that one ugly and inconvenient (I think around XP was the time I tried alternate window managers because the default look was so ugly). The modern look with the icons and icon-actions is perfect for a vertical taskbar