When comparing PuTTY vs kitty, the Slant community recommends PuTTY for most people. In the question“What are the best SSH clients for Linux?” PuTTY is ranked 4th while kitty is ranked 6th.
Ranked in these QuestionsQuestion Ranking
Pro De facto standard client for SSH, Telnet and Rlogin
PuTTY is one of the oldest and most popular clients. It has earned the trust of a great number of users over a long period by being reliable, offering useful features and helpful support. It got into the 15 Essential Open Source Tools for Windows Admins list by InfoWorld.
Pro Source code available
Full source available. Compile and modify it yourself.
Pro Lightweight and portable
Pro Tabs for multiple instances
Operate several terminals from one window using the tabs feature, allowing you to make simultaneous connections to different remote hosts.
Pro Window tiling
Very elegant keyboard shortcuts for creating and navigating between tiled terminals within each tab with no appreciable lag.
Pro Controlled and configured from the shell prompt within the program itself
No graphical menus to clutter the screen saves system resources and time once you learn that all those options are still available from the command line within the app.
Pro Extensible Kitten framework
Supports plugins to add features one at a time for those who need them. Examples include Unicode input and side-by-side diffs.
Pro Scrollback buffer viewer
Allows for viewing the scrollback buffer in an external pager of your choice ('less' by default, with support for 'more' and 'most'), a huge benefit for turning actions taken in a live terminal session into a script for efficiency or dissemination or collaborating on workflows.
Con Can not save passwords
Anyway, you can use "PuTTYgen" to generate a key pair, then use "Pageant" to do a password-less SSH remote login.
Con Lacks features
It is JUST an SSH client. There are many other options with built in X-servers, Multitabbing, etc.
Con Tedious logging/tracing
Its tedious to set up logging and tracing (e.g. for serial connections).
Con Ugly design, too simple
Con No global settings
If you want to change a setting for all your connections, you'd have to do it individually.