https://www.rtings.com/headphones/tests/isolation/noise-isol...
This gives Bose QuietComfort 35 overall attenuation -27.08 dB, which is only beaten by the Sony wh-1000xm3, and some Etymotic in-ear buds.
Notably that number is more than 2x the attenuation of the Momentum, at -12.35 dB.
Usually a person won't notice an increase in volume unless it has a 3-5dB (3dB = double in power) increase. And won't perceive a double in volume without a 10dB (10dB = 10x increase in power) increase and even then it depends on the specific frequency.
Some things to check out would be: https://en.wikipedia.org/wiki/Stevens%27s_power_law https://en.wikipedia.org/wiki/Weber%E2%80%93Fechner_law (and thus Just Noticable Difference [https://en.wikipedia.org/wiki/Just-noticeable_difference])
Their build quality and sound is also pretty good. I have a decent music background and also have Sennheiser HD650s which the audiophile crowd loves, but I think their build quality is cheap plastic (they're also open, require an amp, and cost $400).
I think the Bose hate is mostly tribal nonsense - it's cool to signal audiophile virtue by hating a dominant brand that lay people like.
I think most of the Bose hate comes from their speakers which cost quite a bit for the sound quality. Much of that might be historical.
These days though I don't think anyone buys Bose products solely for their sound quality, they buy them for specific use cases like noise cancelling, or filling a room with a very small speaker (those Bose sound docks were pretty incredible when they came out). Bose has done a good job at doing something unique while offering sound quality that is mostly good enough.
I happen to have a pair of those, which I chose over the QC35s, however I would disagree with GP that their ANC is superior in any way - at best it's almost as good as the QC35s.
I bought them because they were more comfortable on me, the ANC was good enough for my occasional use, and I liked the way they look.
But there's half a dozen other Momentum headphones, some with, some without ANC. Sennheiser's naming schemes are aggressively unhelpful. Just look at this small subset of their overall headphone selection (hit Show all): https://en-de.sennheiser.com/music-headphones-portable
Naturally, they don't call it ANC, it's NoiseGard™ [sic].
They are not the 100% best sounding headphones. However, the clarity and imaging they provide is pretty astounding and I think they compete with any similarly priced competitor. I'm the kind of guy that will take speakers over headphones any day, and I find myself using the QC35's more than my speakers these days.
I have a pair of AKG K271 mk2 at work (same category as your HD280), as well as the Bose QC35s. The AKGs give a bit less isolation, but for extended use (6-10h) wearing comfort as well as audio quality, they blow the Bose right out of the water. The QC35s have been relegated to travelling only.
It just depends.
Barring subjective things like sound quality that I'm really not comfortable weighing in on, I just haven't found the Bose products to be fundamentally flawed in terms of build quality or noise cancellation.
It may vary based on your office -- I don't have some crazy person simulating machine guns on a mechanical keyboard 3 feet away or a super loud, pure open office space with warehouse ceilings either.