When I go to a busy restaurant during lunch with my headphones, I feel like I'm by myself with the QC 15's.  They work fine with your iPhone but if you get an Amp, you can change the setting on the headphone jack to Lo.  Then, you can crank the Amp and you get some pretty good sound when you are at home.  In my opinion, if you listen and get used to their sound, you'll be happy with the sound.  Also, they fit well on my head, which I like.  I felt like the other headphones (Parrot Zik, UE9000, UE6000 and others) moved around when I would walk.  I don't recommend this, but they are GREAT to workout at the gym.  I bring my iPad and can watch a TV show in a busy, noisy gym without having to crank it. 
 
Don't get my wrong, you will hear sounds from the outside world, but they are sounds like someone talking or a siren.  These headphones take out the background noise.  Also, you can get these for under $200 used since they've been out for years.  You won't get the Apple cord, but you can get that online.  You will lose a little sound with the cord not from Bose, but it works and it's so nice to adjust volume, skip songs, etc.

For $199 or below, I couldn't find a better headphone out there.  Having the batteries in the headphones allow it to sound great with just my phone.  I got some higher end headphones, but I had to use an amp to get the sound out of them.  First, I went 4 1/2 starts, then I changed it to 5 because if I have my music going at a medium volume, I don't hear anything at an airport or loud restaurant.  Again, the canceling isn't as good as the Bose Q15's and I haven't heard the 20's yet.  Also, I had the Bluetooth version of this headphone and wish I would have kept it because no wires are great even though I lost some sound quality.  But, I needed the $200 at the time.  Hope this helps!