When comparing PuTTY vs Xshell 6, the Slant community recommends PuTTY for most people. In the question“What are the best terminal emulators for Windows?” PuTTY is ranked 7th while Xshell 6 is ranked 9th.
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 Can be used on any Windows computer, even without admin rights
Pro Lightweight and portable
Doesn't require much resources (memory and hard-disk). Can even be run on a system by just downloading without install.
Pro Connections management
Pro Has tabs
Pro Local shell interface to control Xshell
Pro Great option for enterprises
Xshell 6 caters to enterprises with features such as multi-tab UI, dynamic port forwarding, scripting support, support for ASCII as well as non-ASCII characters, etc.
Pro Compose bar to send a string to multiple servers at once
Pro Can use any system font
Pro Tunneling bar
Channel monitoring and dynamic port forwarding.
Pro User defined key map support
Pro Task automation with VB script
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 Ugly design, too simple
Con Tedious logging/tracing
Its tedious to set up logging and tracing (e.g. for serial connections).
Con No global settings
If you want to change a setting for all your connections, you'd have to do it individually.
Con No login scripting
Con Not free
The subscription costs $89 per year.
Con No stable portable version
Any portable version present is wrapper. It moves files from portable folder to appdata and backward, which often cause dataloss