You can always use the basic uploader before you start your listing so that you won't have to use the fancy new one while you are making your ad. I personally LOVE the new uploader--the basic one always seemed to freeze up and you could only load small images. But with the new uploader, I haven't had a problem--no failures due to the image being too large.
I have actually saved a lot of time using the new uploader--I drag entire folders to the bottom and hit upload. That's a big time saver! I don't recall the basic uploader being able to add images that quickly. It drove me nuts--You had to hit "browse" and click on each image you wanted, one at a time, and then hope that they aren't too large when you hit upload.
I will never ever want to use the basic uploader again.