I've used most. Caterpillar had litterally dozens of programs, now they use Pro-E, Pro-Harness, etc. yechhhhhhh!!!!!!
Around my office, I usually use AutoCAD LT, but sometimes real ACad.
At Siemens, I has ACad R14, 2005, and Promise-E. The ACad programs were FAST! Promise-E locked up a lot, it took 10-20 minutes to load sometimes, could use a lot of the ACad commands, was very difficult to do simple ACad functions if they would even work. For what extra stuph Promise-E did, it was not worth the money because you had to redo so much, like move wires on the schematics.
I loaded something last summer, can't remember what it was. The ICON was flourescent green, did charts and flow sheets great, but electrical or mechanical drafting were a joke. Then I start getting several emails a day from the manufacturer that appeared to be driven by the contents of my emails, so I deleted it. Wish I could remember the name. I need to go through the old threads.
Tom uses a nice alternative to ACad, but the name escapes me. If I had to buy one, that's what I would get! I think it's called DesignCad.
Here is a similar
thread that surfaced a few years back.