The local Government basically gave up - as with all the other invasive species - too much discussion up front, too many opinions about how cute/musical the species is, too many committees and minimal but very ineffective action.
Some area in Hilo are as bad as anywhere in the islands in terms of coqui noise. In regards to the volume of noise in zip code 96740 you really need to be more specific. As one agent mentioned, 96740 is a huge area. Some subdivision are on the case and work hard to remove any coqui as soon as one makes a sound. Other areas, no one is doing anything about them. At this time nowhere in Kona is as bad as Hilo. That being said you really need to check out any area (during the evening) where you are thinking of buying. Best not to rely on anyone's opinion as noise level is really a subjective issue. One thing is for sure is coqui's are spreading rapidly all over the island and unless you are in a desert climate you can count on them showing up one day or another.