We just looked at a drop test comparison between the new iPad and the iPad 2. The new one is more durable (it's also heavier). Now, let's see how they stack up on speed.
Being faster was supposed to be one of the big selling points of the new version (in addition to the retina display, camera, etc.). It looks like they're pretty close on speed, however. If the new one is faster, it appears to only be slightly so - to the point where it would be practically unnoticeable.
Redmond Pie put out this speed comparison video:
This might make you think harder about which one you want to purchase (assuming you actually do intend to purchase one). Apple did drop the price of the lighter-weight iPad 2 to $399 for the 16GB WiFi-only model and $529 for the 3G version.
They also compared the cameras in a nice split screen format:
Again, based on the video, I'm not sure the new one is so much better, it's worth the extra money, for the average consumer. For professional photographers, actual cameras are more likely to be the instruments of choice. Of course, the price on the new iPad is sure to come down as soon as they put the next one out.