I have a the Sennheiser HD595 and the bass is significantly lacking on these to my ears. The bass on my Denon D5000 is great, but I can nearly achieve a similar level through modest EQ'ing with the Mad Dogs with Alpha pads. The bass should be more than adequate, but if you can EQ, there is no question the Mad Dogs would be able to fit the bill with regards to bass quantity. Also, the closed design of the Mad Dogs is a significant advantage in many ways to a more open pair of headphones, depending on the environment you will be listening to most often.
I use them at home, so isolation isn't an issue. I was a little worried about getting a closed over an open headphone too. I was afraid of losing out on openess and an airy sound.
Also, which amp do you use with your mad dogs?