we installed both the ones from summit, the lower operating vacuum one first and then the higher one. They are fairly noisy but it you rubber mount it and have any kind of motor/exhaust it covers it off, that said you'll never get used to the random vibration of it cycling.
Was it worth it? if a big cam and soft brakes then yes, if its just to hold you over until a brake swap just get used to the heavy pedal and remove/break the valve in the booster.
