Ease of use and integration with plugins are some of my favorite parts of leiningen. I also found the documentation to be very good. Whether writing a simple clojure library, commandline tool, or web service, leiningen's support for templating those projects and building them was superb. Highly recommend it.
What do you dislike?
It's a bit clojure-centric. While I wish all dev projects that I supported were done in clojure, many of them use different languages. I wish I could use leiningen for everything because it's much more user friendly than maven/ant.
Recommendations to others considering the product
Get involved with the support community, they're great.
What business problems are you solving with the product? What benefits have you realized?
Creating/building small, single-purpose applications in clojure. Leiningen makes it easy to manage dependencies, setup and build projects. It also integrates with tools like immutant (to host clojure web apps).
* We monitor all Leiningen reviews to prevent fraudulent reviews and keep review quality high. We do not post reviews by company employees or direct competitors. Validated reviews require the user to submit a screenshot of the product containing their user ID, in order to verify a user is an actual user of the product.