co2 controllers and burners need help?????

i see all these diffrent types of co2 controlers and burners on hydrofarms website what are the advantages and disavantages with there diffrent co2 devices cant decide what burner to use, keep hearing that fuzzy logic is a must with a controller and as far as burners go which one would be easiest to cool and hook up, is okay to have over kill when it comes to burners im using a 12/12ft room for veg but want to be able to move into flower 20/50ft with same burner, will the only effect be filling room with co2 faster. please help cant decide on what to use but im heart set on hydrofarms products..