Miraz -
There are benefits available if the engine can be run lean of peak (LOP) automatically. LOP operation in a TSIO-520 can result in saving 3 to 5 gallons per hour at the same TAS. With todays (and tomorrows) fuel prices, that can be HUGE.
LOP operation is becoming more common in GA engines (especially turbocharged), but it requires a properly set up engine, some training, probably a multi-cylinder engine analyzer (to watch EGT and CHT continuously on all cyls). The FADEC system being sold by TCM operates the engine LOP during cruise (but ROP for high power ops), and some engines (like the Piper Malibu/Meridian?) require LOP operation per the POH.