With Alpha 3, the GTK2 interface is in very good standing. Almost all features are implemented from the GUI, there is the ability to configure preferences and graph options from the interface, and much more. There are screenshots and more information on the Phoronix Test Suite 1.8.0 Alpha 3 interface in this Phoronix Forums thread.
In Alpha 3 the SVG renderer back-end to bilde_renderer has also been improved. The bilde_svg_renderer is now beginning to optimize what is outputted for efficiency, a smaller file size, and greater compatibility against SVG viewers. Prior to 1.8.0 Alpha 3, the bilde SVG renderer would average about 6~9kb per graph for its file-size, which isn't bad and still much smaller than using say the JPG or PNG renderer. However, with Alpha 3 that file-size is now averaging 3~4kb while still conforming the the W3 SVG specification. In fact, for Phoronix Test Suite 2.0 it's being considered to make the SVG renderer the default renderer instead of using the PNG renderer by default, which depends upon the GD library. Feedback though is welcome.
The latest version of the Phoronix Test Suite can be downloaded here. The next development release will be Phoronix Test Suite 1.8.0 Beta 1 and it's currently targeted for release on the 24th of March.