Not specific to iOS except in so far as I will be using them on an iPhone 6 (and Macbook Pro and iMac).

Looking for quality ($300-$500)  headphones for use with the machines above (playing Apple lossless and high res audio files).

Need to be easy to drive, preferably with case etc for travel. They do not need to be noise cancelling as I have some Sennheiser 550's for that. More about audio quality.

So far my shortlist is

1) B&W P5 Series 2
2) KEF M500
3) Sennheiser Momentum

I like the look of the B&W P7 (and they review very well) but the NZ price is pretty high ($750) compared to the US - best option for those is to buy them in the US on a visit, where you'd save nearly $300 compared to here.

Anyone have any of these? Or other suggestions?

I mostly listen to Jazz and stuff like Fleetwood Mac, Steely Dan, Dire Straits, Santana etc. and prefer a 'warm accurate' delivery rather than 'cold analytical' or 'heaps of stupid bass'.