Hi Kevin, At Loral Aeronutronic (formerly Ford Aerospace) we migrated from Sci-cards to Cadnetix and 4 years ago to Cadence. We established evaluation criteria to meet our requirements and evaluated 4 CAD systems with a benchmark design. The benchmark represented our most complex pwb (at that time). The companies competing were Cadnetix (Intergraph), Mentor Graphics, Cadence and Computervision (Theda). The benchmark hands down was won by Cadence and the Prance XL router was most impressive, completion time as well as less routing layers. Another requirement that we had that highly contributed to our selection was simulation. Also a big concern to us was conversion of libraries and data bases from CDX (D). As you may remember, we have pretty stiff documentation requirements being a mil house, level 3 drawings prompted us to develop our own in house library of schematic symbols to meet mil/microfilmability requirements. We xferred CDX libraries and several boards in work. Cadence tools definitely have a steeper learner curve!! I found Cadence AE's to be extemely helpful and actully rode shootgun with us during our first designs. Presently we are under the Sun Os (unix) operating system but we will be changing to Solaris to be compatible with Computervision our mech CAD system. We have been sucessful in xfering mech board outlines from CV into Allegro, populating pwbs and then xfering back to CV for component nesting studies. Since our CDX days our designs have become denser, and finer pitches, double sided, fine lines. We have been very sucessful using Cadence Concept (schematic capture) and Allegro (pwb layout) tools. I would highly recommend Cadence Design Systems. p.s. Enjoyed your article in Printed Circuit Design Dianne L. Boehm Loral Aeronutronic Rancho Santa Margarita, CA 714 459-4490 [log in to unmask]