I don't think you are paranoid. Wood floors are expensive and easy to ruin with water. I have seen a few threads about leaky canisters, but I would not say it's common that they leak. When they do, it seems like a bucket would almost always contain it, IMO. That being said, I have also seen a few threads about leaky HOBs, (not sure exactly how these would leak with the overflows they have, though). So that may be a wash. I use HOBs myself, they're cheaper and maybe easier to maintain. I like the sound of running water. But canisters have a lot of benefits, as pointed out above. If there's room in your stand for a big bucket, I say go for it, try the canister. Home insurance typically covers water damage from aquarium accidents anyway (but who wants to file that claim). Good luck whatever you decide!