When I did testing of the new UI, I really hated it. The foremost issue is that it is just ugly. I asked if we could keep the original UI as "basic mode" and the new UI as "advanced." The new UI is just not intuitive, and even fewer people are going to take place in the market because of it.
I am not an ebil marketeer, but I do use the market quite a bit -- this new UI makes me dread it and want to have nothing to do with it.
To be constructive:
Please get rid of the vertical display; that is, put items back in horizontal columns -- please!
Get rid of remembering the last bid. People can just paste in amounts from their clipboards if they need that feature. If it has to stay, please provide a way for those of us that hate it to opt out of it.
I am really trying to approach this with an open mind, but I really wish they had not changed the market interface.