I asked that just a few pages ago.
Comfortable is for sure, but still can't find a detailed impression on sound change from the stock pads.
Ok so this is going off memory for the just the pads. I have since done Lawton tuning, and some slight mods found in the TH 900 thread.
First, The pads slightly move the driver away and forward angled. This results in sound that appears to come more from the front. This is apparent to me with recorded music. I think driver distance is more responsible for this than the angle. For EDM and such the difference was not much that I can recall.
Sub bass was slightly decreased due to the fact that the Lawton wrap around the mounting plates more (hard to visualize for the person that haven't seen these mounts) and thus cover 4 holes that the mounting plates have, These holes serve as driver loading "ports", and when they are covered result In a decrease in low frequency air movement. If I had to quantify it, I'd say a 2db decrease in SUB BASS. Anything above Sub bass, actually seems to increase in tightness. Still has that nice lush low end sound. Cirez D's - "On Off" is a bassy track that has an opening bass line where I noticed sub bass decrease.
Mids come forward a bit perhaps due to the driver distance, and I think also because the bass gets tighter, it allows the mids to show through more. Vocals sound more.... There. it's minimal but there is increase. The big increase of mids for me came with the Lawton Tune up kit, but thats not what we are discussing here..
The highs actually didn't change too much for me, with just pads. They stayed just about the same with certain notes in the 8khz range being slightly sibilant if I turn the volume up. Natalie imbruglias "torn", almost made my ears bleed. That song is mastered in a way to really bring out the sibilance. Again, after the tune up, the highs smoothed out. Not less highs... just smoother and not so sibilant
So in summary let's say the pads make the V shape of the headphones more obtuse. If before they were V shaped headphone, now they are a more Wide V. More flat if you will.
Comfort again is the total name of the game with the Lawtons.
Edit: I'm using them on TH-600, so YMMV