I wouldn't necessarily count out gyres just yet on noise alone. The noise is really, really subjective. One reefer will state that while it was louder than an MP40 it was still very quiet and they had to put their ear to the tank to even hear it, while the next reefer will compare it to a chainsaw. So what I guess I'm saying is YES, they are louder than an MP40, but NO they are not "loud" and it really depends on how sensitive you are to any noise from the tank and where the tank is.
I'm really back-and-forth on it, because for the nearly $700 price point I could get a pair of really beefy Gyres and run them both at low percentages and probably have virtually no noise and sill probably save a hundred bucks. By far I am having more trouble picking a flow option than any other piece of equipment.