Without knowing anything else, I'd say the browser interface is preferable. Especially from the user end. The browser interface could be accessed from most any computer on the network, with an interface that even the newest user will find familiar. Also, it's the back end for a web app, so a web interface seems intuitive.

The downside of a browser interface is you'll have less control of the interface and will have to fit your app into the browser's constraints, particularly the stateless environment.