First to say, I would like to give TST 5 stars, but with
a) Missing Search Function (more to that later)
b) Missing Savestate Function (more to that later also)
it cannot have more than three.
Unlike User Coolvibe, I have no problems with TST for more than a year. I have always about 900 - 1000 Tabs open. My OS is Win10 x64 with 16G of RAM, and pagefile is off. After a restart, it takes about 10 seconds to initialize TST icons, but with that much tabs it is ok. I would recommend to anyone who works like me to run process explorer to look at the memory consumption. If it reaches the maximum, which is easy in Firefox by changing between Tabs, FF becomes instable, and Tabs will begin to crash, maybe due to my deactivated pagefile.
I think that FF needs a lot more memory with TST, and maybe user Coolvibe is on Win32, which isn't really suitable anymore for some applications, FF included, because the devs do not care very much. I have on another machine a 32-Bit FF on a 64-Bit Win10, and it isn't as stable as the 64-Bit-FF, so maybe Coolvibes' problems are from there.
To paragraph a)
That is a very arrogant behavior of the TST devs to say on their page THAT REQUESTS FOR A SEARCH FUNCTION ARE IGNORED. Why ? The Opera/Chrome Sidewise has this. I am eager to know why a dev spends dozens of hours for a sophisticated program like TST, and refuses the most useful and simple functionality EVERYONE needs. I know people who are constantly using 2000 - 3000 Tabs and would be VERY HAPPY to have a simple search button. And NOT by installing ANOTHER addon that needs permissions to this and that.
To paragraph b)
A SAVESTATE Function would be very helpful in case of a heavy FF crash (that happens sometimes) or migration. Where tree informations are lost together with all open tabs. I use Tab Session Manager, but sadly, it doesn't save the TST tree informations. At least it didn't the last time, so my restored tree was completely flat, and I had to spend an hour or two to make new indentations (remember, 1000 tabs...).
Conclusion:
TST has a lot of useful functions, it grew from nearly crappy to very stable and relieable during a short period of time, but the focus went off a bit from real usability to functionality overload. I couldn't even find a SIMPLE function to give the active tab a special color. Maybe I'm too dumb or too impatient. But there are even several addons that are extending TST, and they do not fulfill the aforementioned search and savestate functions.