There are a lot of EDA (Electronics Design Automation) software packages out there. This post briefly talks about what I consider the high end professional ones. There are ton of zero cost or low cost but these are typically for hobbyists or very small companies (KiCad, Eagle, DesignSpark, etc..) which will not be covered.
I have used Alitum Designer the most, by far, having only used OrCad and Tango (old and no longer around) a little. I have used Pads and Allego viewers a little.
OrCad + Allegro
From Cadance, a lot of engineers like OrCad (schematic) but dislike Allegro (layout). Allegro is good at routing but has a very bad footprint builder and it hard to learn. They tend to be very popular with larger companies and engineers who have been doing design for a while. OrCad’s CIS system is well established at larger companies.
DxDesigner + PADS
From Mentor Graphics, a lot of engineers like Pads but dislike DxDesigner. Pads is for layout, tends to easy to use and learn. DxDesigner is for schematic entry and most dislike it… in fact I have not meet anyone who likes it.
From Altium, many engineers like Altium Designer. It is a unified package and tends to be popular for it’s lower price and new features. It’s unique in that it was designed from the ground up to be both a schematic entry and layout tool. Engineers who use it like but but people coming from Pads/OrCad/Allegro generally look down on it. It has a perception of being not as “professional” as the older software. It’s electrical to mechanical CAD features tend to stand out and be very advanced when compared to others. The pricing for Altium Designer is much simpler than the others.
See the Wikipedia entry for further details. Getting really good at a software package takes years of use thus learning a new software package is not easy task.