Significant improvements have been made to the general systems in place.
Overall: Less packets are being sent, less items are being shifted around, and everything should just run a bit better. There's less duplication of objects, and a ton of the code is now more extensible (meaning mods can interface with FB way easier now!) and reusable.
Additionally, the player crafting grid is now supported, so you can craft lag-free in the 2x2 grid. This part requires a coremod, but it is done as non-invasively as possible (it requires two hooks, one to properly handle shift click crafting and one to handle grid updates). Both hooks just call code that FastBench uses for the 3x3 crafting table, with nearly nothing special needed for this support. Any mod wanting to support their own custom crafting grid should be able to do so in a similar fashion.
This is marked as beta as this is largely untested with mods, but it works perfectly in a vanilla environment.