What makes it so good is you can have item tesseracts interact with AE via some of the items AE adds. This means you can set a tesseract next to a quarry and have it get sent immediately into your AE storage and sort it from there if you like. You could even set up an AE system that is designed specifically to sort out specific items to different areas via tesseracts and into other areas for processing, then have the processed goods enter the main AE storage system. For example you can have it export dirt, cobble, sand, etc. towards a tesseract for either recycling or voiding, set up a system to export ores than can be turned into dusts, and then send anything that you want to keep but can't be processed into either a different AE system or into another system such as RP2.
Basically, there are a ton of ways to manipulate AE as well as plenty of ways to sort out some items from others, be it using a multi-step process or a single step one. As one would expect AE also melds extremely well with item tesseracts AE's system for handling items can easily keep up with how much throughput item tesseracts can deal with. Do note though that each item transaction puts more load on your energy usage than the standard power usage for just keeping the system running.