Qualtrics is being used specifically by the Public Policy Research Lab here at LSU. We're essentially a market research unit that serves both on-campus clients, non-profit's, state agencies, and businesses. Whenever we have an online survey to do as part of a research project, we host the survey in Qualtrics.
Qualtrics is extremely intuitive and easy to use. You sign in and the rest is pretty self explanatory if you're even loosely familiar with survey design.
Qualtrics offers unique randomization options by allowing the users to group questions into blocks, and questions can be randomized within the block, and access to the blocks themselves can also be randomizes.
Qualtrics offers great options for referencing previously entered data in new questions.
Qualtrics offers a unique heat-mapping tool to track where users click on a website or other supplied media.
Testing surveys can be difficult, as the steps to test in the middle of a survey, rather than at the beginning are not always clear.
Numbering questions in Qualtrics is extremely frustraing, as the product defaults to numbering questions by when they were added, not the order they appear in the survey. This makes referencing extremely difficult.
While Qualtrics does offer the ability to screen respones (such as ensuring the entered data is a Phone Number (xxx)-xxx-xxx or a date xx/xx/xxxx) - learning how to use those functions is somewhat obtuse and confusing.
Qualtrics does help with our response rate on surveys, as if we have the respondents email address and names, Qualtrics can send a personal email message to them, and Qualtrics can send reminders to non-responders.