Looking for a tool that will help me understand users better during testing.
What kind of testing? http://www.usertesting.com/ gives you a video + audio of people testing your website / prototype.
We do both in-house and remote testing. While there's no substitute for having a user in the room with you (all types of non-verbal feedback cues), we have had some luck with remote testing. Gotomeeting has worked pretty well for us. It allows for recordable video interviews, as well as screen sharing from either participant. We've had users click through mockups on any one of the online prototyping tools (invision, etc).
We've also been able to share our screen with them, give them control of our mouse and keyboard, and allow them to click through live development builds without having to distribute the software.
Taking the video interviews and throwing them into a dictation software like dragon naturally speaking has also helped us build up a searchable library of interviews to look back through for future needs and research.
Never used it, but there is http://silverbackapp.com/