O.K. I feel like I need to post my rant/backup for Eagle.
First of all, a bit of background. I was trained by the U.S. Navy in electronics, specifically avionics. I went through the navy school which was fast paced and not exactly easy. After going through school I was assigned to an aircraft squadron which was designated an "O level" position. What this means is, if a certain box failed in the aircraft, we simply changed the box and sent it to "I level" to get repaired. The tools of my "trade" back then were simply a multimeter and a TDR. Much of the troubleshooting was utilizing the onboard General Purpose Digital Computer (GPDC).
Fast forward a few years when personal computers first started being "mainstream" or "popular" (early-to-mid 90's). I obtained one and discovered the internet. Back then, a 14.4 baud modem was the shit! I found a few "geeky" BBS's that dealt with computers and electronics.
Fast forward a few more years... Redhat Linux was in it's infancy, and I got introduced to it. I started using it, learned to compile programs and eventually got comfortable with the "clunky interface" and the "quirks" of using X-11. I also embraced the Open Source idea and learned that if I didn't like the way some piece of software worked, I could download the source and modify it to suit my needs. Thus I learned how to program in not only C, but also learned about PERL, Python, C++ and other languages.
Fast forward a few more years and I ran across an article somewhere on the internet that was about Arduino. It captured my interest, and I dove into playing with one. Then, I started seeing that I could do more complex stuff with other AVR chips, and I started doing that. Then, I discovered that I could do the same stuff with a PIC, an ARM Cortex, etc. and I got the "bug" to get back into electronics again.
When I first was introduced to Eagle, much of it was centered around doing Arduino stuff. Since I had a background with Linux and the tools available, I was able to adapt easily. Yes it is a bit "clunky" if you use "professional software" such as AutoCad, but for me it was quite easy to learn, use and work with. Is it easy to work with and use? For me the answer is yes. Does it get the job done? Again, for me the answer is yes. Is is a professional piece of software? I would say no.
The bottom line is, Eagle isn't targeted so much at the "professional" crowd. I would venture to say that the target is more the hobbyist (like me) and for that it is a fine piece of software.