There are many subtle differences: as you noted, the rows per page differs; clicking to select all offers "Select all conversations that match this search," rat

There are many subtle differences: as you noted, the rows per page differs; clicking to select all offers "Select all conversations that match this search," rather than "Select all conversations in <Label>"; the "Remove label <Foo>" button disappears; an Archive button appears; "Move to" disappears, but "Move to Inbox" appears instead; etc. It's not broken in the sense that it doesn't work, but it's broken in the sense that Google's implying an equivalence that is not there.