Making my entire workflow much slower. In the previous version I was able to type a single letter "b", and the first thing that starts with the letter "b" in the current folder is being selected in an instant (less than 30ms would be my estimate). Now I was able to use my scrollwheel to quicly move the selection to the folder/file/thing that I actually wanted. 
Why did this work so well?
90% of the time there are only approx. 3-4 items with the same starting letter in the current folder. A quick scroll is much faster than the new Nautilus 3.6 workflow, where the search is 
1. slower, about 500ms everytime
2. It removes the rest of the folder from my view which creates numerous problems with only a single advantage(more focus on found items since all of them are in the same view now). Most of the time I quickly have to move right back to where I was, but Nautilus 3.6 search requires extra mouse navigation and clicks now to remove the search bar or the pressing of the escape button. This is much worse than just being able to click into the folder view like I was able to do before because I was going to need to continue working that folder view anyway. Clicking in it is significantly better than having to move my entire left hand to the escape button to continue a workflow that I will need to continue just about every single time I do a search in a folder.

Please reconsider and implement an advanced version of what we had before. Look at how popular the Google Chrome full text search has become, every other browser is adopting it now. This is just an example of the philosophy of what I personally think makes search great: realtime results in the same view that I'm working in.