@p XCF is the gimp version of a PSD for most practical purposes. You can save layers, layer style, paths and color channels in a TIFF, XCF and PSD. XCF and PSD can also save video, which is really where they have anything over a tiff.

If you want to open a XCF file in photoshop, you can download a plug-in or, better yet, save the XCF as a tiff - it will preserve, at a minimum, your layers. Even Corel Draw will accept tiffs.