While that saying might be a tad unjustified, I find that their products are often purchased by people who don't do adequate research into other headphones that might suit them better. I often see people wearing the "QuietComfort" brand headphones in situations where they gain no benefit from active noise cancelling, although for all I know they could be heavy travelers and only own a single pair of headphones. But honestly, a comparable pair from another brand would run them $200 less...
The only time you really want the active stuff is when you're traveling and there exists a lot of low-frequency noise, such as on a train or airplane. Looking around on Hydrogenaudio confirms that the QC are okay if that's all you need, and also that alternatives exist, such as IEMs, which might have a wider range of use as they simply have very heavy passive isolation.
Here's what the wirecutter says about it: http://thewirecutter.com/reviews/best-noise-canceling-headph...
At home I also have the Sennheiser HD 600. I usually use the Bose -- the noise cancelling is nice even if you're not in a plane.
I'd be upset if my home environment were loud enough to warrant noise canceling, though.
The e5c's main problem is they are SO sensitive they are completely unforgiving about the amplifier used - almost anything with a gain block after a volume control is going to have too high an intrinsic noise floor for them to not show it up.
In terms of pure isolation, Etymotic makes some of the best out there (>30dB isolation), and I think they sound absolutely brilliant.
Bought some QC15s at 2 am in the Atlanta airport on a cross-country-twice-in-48-hours trip. Probably the best $300 ever spent. Slept like the dead. No one bothers you with those headphones, and they aren't nearly as heavy as a lot of fancier stuff, or as insulated, so your ears don't sweat.
Those are my go-to ears at all times. I even got a carabiner so I can clip them to my bag (also a superb product: http://www.saddlebackleather.com/Classic-Briefcase-Thin)