I just got the update, and yeah, this was really badly done.
Apparently loading the market now starts on your downloads list, which I find to be rather useless - I'm in the market to search or browse, and already have the main app list for this...
The curved upper part is pointless and just makes it feel more cramped, since it blocks most of whatever's at that part of the scrolling. It also keeps changing size, depending on what part of the Market you're in, rather disorienting.
The amount of lag is at the HOLY CRAP level, at least on the main screen that contains "Featured Apps". I had to put my phone down and wait just now because it completely stopped responding..
Now, let's go into "Apps"...
There are new subcategories, which is nice, but the Featured Apps are still there. Why? It's just a waste of space at this point.
Selecting an app, it's just a big mess. The curved upper part that has contained nothing but "Featured Apps" and the selector for Paid/Free/New now contains the image, name, and install/open/update/uninstall buttons, as well as the rating. I did ignore it for a short bit, expecting more ads, but then I realized - all the update/install/etc buttons in the entire market have been moved from the bottom of the screen to the top. And they're smaller, and their styles are different, so it's not immediately apparent.
Why is the Description automatically in "Less" mode? What happened to the nice tabs for Description, Comments, and Related that I had - now it's all smooshed back onto one page MySpace style..
I also see Allow Automatic Updates takes up... Wow, 3 lines, large gaps, and 1/3rd of my screen. Much more than it used to, for identical functionality. Again, why?
I think I'm going to redownload the AppBrain app for my searches. The "Update All" button is all I'll want from here.