Multi Quote
When you're looking at the posts on a thread, each one now has an additional button "multi quote" and if you click it, the button will fade. You can pick as many as you want, I think, but at least 4 (I tried it). Then, when you post reply, the window has all the quotes from the buttons you clicked. If you want to unselect a quote, you click on the faded button and it will not appear in the reply box.
I haven't tested it much, but from what I can see it posts the quotes in the order they were originally posted and not the order you choose them.
Quick Reply
This box is at the bottom of each page of the thread, just before the New Topic and Post Reply buttons. You can just type your post there instead of going to another page.
If you click on the far right button (Switch Editor Mode) you can switch between viewing your reply with the BB codes or as WYSIWYG - or so they'd have us believe. (You can also do this in the regular post window.)