The UI is clean and to-the-point. The features are sufficient for most day-to-day use, but for anything more advanced, I guess you’ll need to use the command line or other tool.
To be honest I haven’t yet seen an advanced enough GUI for compression purposes on Linux, perhaps like WinRAR in Windows.
For alternatives, Kubuntu’s default is Ark, which is okay, and I think is comparable to File Roller in many ways. Xarchiver is also available (GTK2), and is somewhat similar to File Roller. These applications just work and there aren’t too many bells and whistles to expect.