It is a very good piece of software. It has some strange quirks but once you get used to it, there is a lot of powerful stuff going on. Being totally new to it, I spent a while getting comfortable and building my own library but now seem to be moving along nicely. For example I spent several days creating about 20% of the Amplifier Board circuit diagram (schematic) using Eeschema but then brought that total up to around 95% complete in one day.
Although designed for Linux, I am using it on a Mac using OS X 10.7.5 and it works absolutely fine although there are some little things that are strange to a Mac user.
I can thoroughly recommend KiCad to anyone wanting to create their own pcb schematics and diagrams. Plus the help from the User Group is outstanding.