PCManFM has a typical interface for a GTK file manager, which looks a lot like Thunar, the default file manager used by Xfce, reviewed yesterday here. By default it has a left side panel which provides access to all the important locations in the system, including unmounted partitions. I noticed that PCManFM will also automatically inherit Nautilus' bookmarks and show them in the Bookmarks menu and in the side panel. The toolbar offers buttons for the most popular actions (Back, Forward, Up, Reload and Home) as well as a location bar, accessible via Ctrl+L. The side panel can be configured to show location shortcuts or the classic tree view.
PCManFM 0.5 in Ubuntu 9.04
Files and folders can be visualized as icon view, detailed list or compact list, they can be sorted by several attributes, including name, type, modification date or permissions. Thumbnail previews for images are also available. Another feature is the Find files function available under the Tool menu or using the F3 keyboard shortcut. You can search by content, file size, modification date too, and the search field supports wildcards.
It supports tabs, but I couldn't find a way to switch between them using the keyboard (Ctrl+PageUp and Ctrl+PageDown don't seem to work, neither does Alt or Ctrl + arrows).
The preferences window allows to customise the size of icons, to change opening files from double-click to single click, preview images, change colours, set a wallpaper for the place where the files are displayed.
Tree view side panel, detailed list for files/folders and preferences window
PCManFM also allows to archive files to tar or compress them to tar.gz or tar.bz2, and another feature it comes with is the ability to drag and drop files from one tab to another, focusing the new tab when the mouse pointer is above it.
As a conclusion, it's good to know there are so many alternatives out there for the default Nautilus in GNOME. Of course, this may not be of great interest for a KDE user, who will use either Krusader, Konqueror (or even Xfe) as a replacement for Dolphin, but for GNOME users PCManFM deserves a try if you want to switch from Nautilus. If you're looking for a simple, basic and lightweight file manager built in GTK, you can't go wrong with PCManFM.