iOutput

Well I've tried both and it's hard to say which technology is better. While noise cancelling usually comes in full size headphones (or in ear with box for batteries and circuits), isolation headphones are in the form of simple in-hear. If you are going to use them in aircrafts perhaps you should consider both but for your everyday headphones, to use on the office, home or public transports you should go for the isolation. Not only they don’t require batteries, they offer comfortable use and are certainly lighter and more discrete.

As for the technology, noise cancelling is based on capturing the noises from the outside (you’ll notice something like a mic hole on the outside) and creating opposite noise in inverted frequencies, thus cancelling the outside noise. They will usually say how much noise they can cancel and it varies from 70% to 99%, depending on the price and technology used. Sound isolation is based in sound proof foam that is compressed before inserting in the ear channel which will then expand, letting the wrong sound out and the right ones in, that is your music.

Having both, I tend to use the isolating head phones much more often because they are quite effective, light and discrete. You will notice in the market that this segment is growing as more brands (Denon, Sennhizer, JVC, Shure, etc.) are launching these models into the market.

Briefly, what can you get for different price ranges:

The JVC HA-FX33 are good in isolation and sound averagely good, will cost between €8 and €20. Comes with two foam sizes. Great choice if you are uncertain you’ll enjoy this type of headphones.

The Denon AH-C351 reportedly have excellent sound quality and isolation but may suffer too much from wear and tear. Comes with three foam sizes, carrying pouch and will cost around €30.

The Shure SE102 are said to have excellent quality and isolation but there may be issues with lengthy listening sessions, you might not want to take them on your trip to Australia. They will cost about €60.