As a techno dj i find tools(looped techno with minimal dynamic change)essential for mixing techno as they give me full controll over the pace and energy of the music.
I would say that around 75% of the records I use in a set will be tools and tend to use the more song based/structured techno at vital points of the set using them to make more of an impact or for bridging between sections.
The more looped based stuff is best for building energy and groove.
I like to dictate when there should be a change and not let the records do it for me plus i like to be in the mix most of the time I dont like standing around doing nothing I prefer bringing records in as soon as possible and leaving them in as long as needed and I feel that tools give the freedom to do this the best.

Like most people have expressed in the past couple of pages of this thread you realy have to be creative and work these records to get the best out of them by using an extra turntable,EQ,FX(not just a flanger),a sampler,some hardware whatever you can incorparate just dont stand there letting them play unless your Mark EG and your busy breaking stuff, shouting rude words at the crowd and dancing like a mad man.

I belive if you give 10 DJs the same 2 songbased/structured techno records you can garrantee at least 4 of them will come up with the same way of mixing those two records together where as with more tool based records the chances of coming up with the same mix is much less likely(this is just my opinion and not fact)

You realy need to use all sorts of techno to get the most out of it.Its there to be abused and creative with and gives you the fredom to use your imagination this is what techno is all about and what makes it stand out from the crowd IMO ;) .