Having used Eagle, KiCAD, and several others, my current favorite is Fritzing. It's quite easy to use and has a large library of built-in parts. Creating new parts is pretty easy compared to other software I've used. Performance leaves a bit to be desired, but this doesn't become a problem except for pretty large circuits.
I've heard others say the same recently. I've always liked their intuitive breadboarding stuff, though haven't used it much. A lot of user-facing friendliness, which KiCad lacks to be sure.
Normally I'd call out the "built in libraries" as a false thing to optimize for, but since you mention making your own components, I assume you're willing to move outside of that as well, so that's good to hear. Most people assume every part should have a library component which is simply never going to be the case in electronics. Even if there were a library for every component, I usually only trust the parts I have made, verified and tested myself. Been burned too many times.
Nope, still two-layer only. I'm actually pretty disappointed with their PCB UI. It makes a lot of assumptions about the existence of layers, and their ambiguous selection is really bad. For example, I often cannot select a small part for moving if there are too many airwires nearby, because fritzing always seems to prioritize airwires. I end up having to disable the ratsnest layer just to move a part. There's also a move vs create wire ambiguity that's really annoying.
I guess I've just found that this is somehow less annoying than the problems with other PCB softwares.
