There is no recommendation. Use what you find easier, and try the other one if it doesn’t work for a specific action.
For adding new Things, either one should work. But for other zwave administrative tasks, Habmin is safer to use, and has more features. One major issue with Paper UI is that when setting configuration parameters, it will set all of them, not just the one you’ve modified. This can be problematic, especially if there are a lot of parameters, and congests the network. There are two downsides to using Habmin, which Paper UI does not have. Associations groups will be displayed as empty or as an X, and you may need to refresh the page to show Items linked to Channels. For everything else, they are about equal… although I personally much prefer the speed and UI layout of Habmin.