PuTTY was my most favorite ssh client for windows. However, it was unusable for a week without any error messages while other clients work fine. I noticed that the problem should be router setting at border gateway in my university. That's why I have to find a new client. PuTTY comes with sftp support but only text version available right now.
SSH Client has been widely used in my office because of its free license for educational use and its rich functionalities. Unfortunately, it seems so slow comparing to PuTTY. The biggest problem is that it does not support font encoding other than default one (ISO-8859-1 or latin-1). Another problem is HOME and END button do not work at all because it supports only a few terminal (no xterm and Linux). The best thing of ssh is that it cached passphrase for another concurrent session and also sftp.
SecureCRT is my current ssh client. It is fast and fully support publickey authentication based on key pair generated by openssh. SecureFX could be used as a sftp client sharing cached passphrase with SecureCRT. This feature looks like one available in SSH client but it is more powerful with synchronize button.