First consider that my data on vetus is very old and only with one tank. Our Islander 30 had a bladder tank by vetus that had never been used (it was there for looks not hooked up and it could have been on the boat since 1975). We decided to be legal
and hooked it up shortly after we bought the boat in 1988. It began to give off oder almost imediately and we went to a plastic tank shortly there after. My present boat has a nauta diesel
bladder tank for the Dickenson Heater (so no experiance with waste). It has been on the boat since long before I bought it in 05 and although if you get close you can smell the diesel
it is not bad IMO (and my wife doesn't complain about the smell). So if I was putting in a temp bladdder tanks
I'd probably go for NAUTA but I'd be lookiing to get a hard tank soon.