I bought a set of M1570's on the weekend and I got them today.
Right out of the box, I am Very impressed! Of course my real opinion won't set in for another month, after a lot more hours.
But my initial reaction is Wow! Great bass and great mids. Treble is present, but not forward or overbearing.
The first pairing is pretty much perfect. It is hooked up to an iFi Pro iCAN. The X-bass is maxed out at 40Hz. The 3D is maxed out at 90/60+. The gain set on mid and the sound is set on tube. Volume is sliding between 9:30 and 10:30, depending on the music. It is killing it with my test list. The bass is booming, when called upon and the vocals are sounding great, both male and female.
These are definitely miles ahead of the M570's, but I have always believed you get what you pay for. To a certain extent.
Right off the bat, these sound a lot more fun than the LCD-2 Classic's. So far, great headphone for a very nice price.