It all depends on what tools substitutes you are in need....

For more than 10 years, I EDC on my belt an old PST II, and that makes me a happy taxpayer ... no ... user... <img src="/images/graemlins/grin.gif" alt="" />
The tools I often need are present on this model.
And just recently, I added in my daypack a tool adaptater and some bits I also use, but less frequently.

My only regret : the poor quality of the blade ..

But then, if I need a blade, I have Doug's RSK in my pant's back pocket.