SecureCRT is a powerful tool that have become my main terminal emulator since 2014, and this is because let me connect to all may devices no matter the protocol enryption that is setup,
It have a very nice, clean and easy to use user interface, that is fully customizable, and this is one of the thing the i really like, because let modify almost everthing, color theme, organize my sesions in differents folders, i can control multiples sessions at once in tabs.
You can modify the scrollback buffer size, i don`t know how big, i think is more than 100k lines, but it let you keep a history of everything that is been doing in a particular session.
And one of my favorites features is that give you the power of record scripts that let automate rutines that make more easier that`s repetitive tasks.
The only thing that i dislike about SecureCRT is the price, i know that is a pretty advanced application, but is kinda high the price for just one computer.
Get the trial version and tested before you buy it, and if you are not going to manage more than ten devices, look for another option more affordable.