I am a long-time user of TotalFinder, having purchased it in November of 2010. At that time -- and in consecutive updates prior to Yosemite -- TotalFinder worked great. It gave me tabbed windows prior to Apple introducing them in Yosemite, as well as colorful icons in the sidebar.
Then Yosemite came along, followed by El Capitan, and tabbed windows became an integral part of Mac OS X. But we also lost our colorful sidebar icons and were forced to accept Apple's bland gray color scheme. Blah! I still don't like it!
More headaches -- for developers and end users alike -- ensued with the introduction of SIP, or System Integrity Protection. While I obviously understand the necessity of SIP, nevertheless, suddenly, it became a hassle to install third-party apps such as TotalFinder.
Personally, after jumping through the "Disable SIP Hoop" a number of times, I finally surrendered to Apple and stopped using TotalFinder, because I now had the tabbed windows that I needed built into the system.
But to be honest, I still miss the colored sidebar icons and an easy, risk-free way to keep folders on top, without having to tweak something somewhere in the System files.
All that to say this: While TotalFinder was great in its day, sadly -- and as the developer notes on the page below -- its days are numbered for a variety of reasons. So before you disable SIP and decide to install TotalFinder, I encourage you to read what the developer has to say here: