They aren't really that well designed compared to the competition. Apple can only focus on one thing at a time (and cutting corners on everything else).
Example: LED backlight cinema display? Neat! Then they cheap out using a glossy coating, not even a HUD, no scaler, no inputs, the worst stand in the market for a prosumer monitor etc. etc. etc. You'd think that a company claiming to be focusing on quality actually cares about ergonomics, but apple only care about looks and perceived quality. God knows how they can uphold that image when peoples devices fail constantly, I don't even know of anyone that own a working iPod anymore.
They can't even design the cooling for their laptops decently. They are hot and they are noisy (no margins at all), and it's not like you get anything in return. Buying an apple product you should just be happy if you can even exchange the battery.
As always, there is one thing they do right. On laptops it's the trackpad. But the rest just doesn't impress and is at best on par with the competition (but lacking the extra features (which isn't really a bad thing (most of the time) - but it makes you wonder what you pay for).
Apple has obviously gone to extra effort to reduce EMI interference, probably to keep the charger from interfering with the touchscreen
I've yet to encounter problems with any mobile phone during charging, so that makes you wonder whether apple uses a cheaper touchscreen than everyone else, or if other charges are just as good in regards to the EMI interference or if apple has higher margins than everyone else (which I highly doubt considering the problems apple create just to look good (cable strain relief springs to mind)).