Hi Jules,
I have no knowledge of the EX-II but myself and CharleyL (another forum member) own Delta Q3's. Personally, I think it is a great saw but it is quite old now and not all parts are available. Mine has been very reliable though in all the years I have owned it. The only problems I have had is snapping the tension lever which is made of brass and the flexible air hose splitting. The Tension lever is available from Ereplacementparts.com for $4.74 USD. For the air hose, I simply use a piece of clear hose with some soft aluminium wire inserted into it so I can position it where I want.
It is a "C" arm saw that pivots on a single point. That gives it an arcing cut which is quite aggressive which some people do not like. It may not be the easiest saw to learn on because of that aggressive cut but it is capable of fine work. Most of what you see in my gallery was cut on the Q3. I bought a second hand DeWalt DW788 as a back up saw but the motor died within three months. I now have a Hegner but the Q3 is still going strong.
Rick Hutcheson has some info on the Q3 and a review at http://www.scrollsaws.com/
Let me know if you have any questions and good luck,
Rob