Chia is farmed with storage space like hard drives instead of mining with processing power. This allows broader access to everyday users, and reduces the cost/waste of securing the network in electricity burned or custom hardware consumed. Chia is resistant to farmer centralization. Chia also will include a bunch of basic improvements to the bitcoin protocol: Everything is BLS signatures for better smart transaction support, and it will include a range of bug fixes to things like timewarp while making those fixes available back to Bitcoin.
Only the farmer who had the best proof of space from his farm will be rewarded with Chia coin at each block.