The FX-i incorporates the reduced size Compact Super-Hybrid Sensor (SHS), which provides quick (one second) readings with high precision. The new Statistical Calculation Function (SCF) provides statistical data display or output of weighed samples.
I bought my FX-300 off eBay for under $200. Many of these are used for grow labs and some are still new in the box. Mine didn't come with a breeze shield, but I bought a custom one that's a ton better off another site. I watched them for only a couple of weeks and found mine. Mine has been awesome over the past year.