Lol...wrong!
I still own both. The iPad 4 is noticeably faster in almost any task you can throw at it. For population of my morning RSS reader to rendering photos...exporting a video to downloading and installing updates. Launching apps, browser speed and retention, sync'ing with iCloud in Pages, Numbers and Keynote...I can't think of anything that isn't obvious. The speed of the 4 exceeds the 3 in benchmarks by two fold. You won't necessarily notice double the speed in everything...but you most certainly WILL notice a faster and less 'strained' speed with the latest machine.
Again...I own both. I use both. Daily! The 3 is an excellent tablet. Easily the second best on the market. But if you're looking for the fastest, the iPad 4 is it
J