The SunSpider reading for FF3 is 12076 ms and for the WebKit-based browsers a bit above 14000 ms. For the sake of comparison FF3 on a comparable PPC machine gives approximately the same result but with Safari it's twice as fast. A recent iPod Touch with Safari goes down to 4146 ms, so better performance would seem possible on Efika, too.
edit: Chromium (package chromium-browser) seemed to do the trick. Pretty usable GDocs and WP. SunSpider rating 5172 ms - thank you Google!