Pros: Awesome frequency responce and good isolation.
Cons: Feels weak and fragile.
The first song I listened to with the HD-25 (like with any new pair of heaphones) was Dizzee Rascal's "Bonkers". This is the one track that I know that feels like every audible and inaudible frequency is used in the bassline... It just surrounds you and therefore can be used as a benchmark tool to test audio hardware.
And boy was I convinced instantly, also the isolation is extremely good so all of that really set me on my way!