We are trying to replace HP ALM because it's only compatible with an old IE version, has TERRIBLE UI and disrupts a lot of our workflows. If qTest were a more reasonable cost, we would seriously consider implementing this agile test management suite.
I like how easy it is to save work, the intuitive UI and the color scheme for quick status checks. The layout is straightforward like Rally's and it can be a requirements repository. Integration seems to be easy and possible with requirements and Jira.
I didn't like how many steps it seems to take to set up the test plan folders. Our testing is pretty rigorous and used for FDA - approved medical devices so that some of the default workflows and fields are not robust enough. I don't like that the Actual Results field can be left blank as long as you select a test status.