Originally Posted by RobouteGuilliman
I would say it is hard to compare considering The Tau is a relatively new race and the Eldar is virtually extinct. Personally, if I had to compare the two technologically as of right now, I would say Eldar. They conquered the galaxy and owned the stars, and they still possess the technology that contributed to that.
Not sure if that's true. I'm sure I've read that the Eldar have forgotten how plenty of technology works. It's just they have a valid excuse unlike the Imperium that has practically done everything in it's power to forget.
The Tau are behind the Eldar and will be for some time. Eldar technology manipulates the warp and only one race has managed to surpass them technologically by means purely of the materium.