I don't, but at least one member does. I've read very good things about it. Canister filters, if properly assembled and set up as the mfgr intended, aren't noisy.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-
If the motor is making the noise, then thats a problem. It could be an indication of mechanical defect or another problem. If its making a lot of water splashing, then you should be able to adjust the nozzles to prevent it.
I've got 4 now, 2 204's 1 404 and a new FX5. They are all pretty quiet, sometimes I hear a whooshing sound but that's just air escaping. My biggest complaint is they are hard to prime (supposedly resolved with the new '05 models), and gasket failure. Not really failure, but sometimes when you put the motor housing back on, the O ring doesn't seat correctly. I fixed it by rubbing a small amount of silicone lube on the ring....
It's very big and powerful, I would not recommend using it in anything less than a 90 gal. tank. I have it set up in my little 35 gal to get it cycling and the water is churning! Everything on this filter is big, it has 6 very large sponges, and I have 2 1/2-3 liters of bio in it with room left for a bag of charcoal.
The really nice thing about the FX5 is you can adjust the outputs almost 360 deg. If you are going to upgrade to a larger tank later, you could probably use it if your turt is not a baby. I had set it up for about an hour in my 90 gal and the currents were not strong enough to knock the kids around, but they are all past the 4" mark.
He's 5 inches. I am hoping to someday have a cool little indoor pond for him, once i'm all "grown up" and have a house of my own and no landlord to worry about. 75 gallons is all i'd feel comfortable keeping in the house i'm in now, who knows how sturdy these floors are. I think i'll still keep it as an option...it's a little pricey but boy would that water be clean!