I prefer one in sump, because I cannot afford any leaks. My own skimmer overflowed when my snails spawned, when I used epoxy, & when I used superglue. It would have leaked all over the place had it been on the floor, which is another big no-no.
Actually I have an AP600 (which has an aquabee pump) & still makes noise to the point where my neighbors are complaining. That is why I am looking for a "super" quiet one, which basically means I am asking for a miracle.
Maybe it's better to go with a hang-on skimmer as the pump would be in the tank or the skimmer itself and you wouldn't get the vibrations as you do from the sump or on the floor.
i have one i have not had one problem so far i have it about 3months check the skimmer thread i have some pics. you will get some micro bubbles till it is broken in about one week after that you get zero bubbles out of it let me know if you need more info, mike
You can find a thread started here not too long ago. Skimmer Thread
Both Deltec Turbo and MCE600 are presented in there. The turbo is not loud considering that it uses 3 aquabee 2000/1. As for microbubbles its nonexistent with the turbos as the water must pass through two chambers prior to exiting into the sump. The first chamber is for carbon pads and the second chamber houses a large sponge.