I have a pair of Sennheiser PX 100s which are open backed and a pair vof I grado's
The Igrado's apparently have the same drivers as the £100 SR60's in a cheaper construction. They are superb
The Sennheisers are also very good, slightly less so that the Igrado's but more comfortable
If you like open backed hphones then i would go for the Igrado's (they have a neck band rather than resting on the head which is what makes them less comfotable
The awards issue of WHF state that they are the best portables available and I would agree (for sound)
PS the Igrado's do look quite cheaply made but are very robust