It's been 2yrs using the Zero system now and am happy with the purchase except the issue with the pour spigot leaking, very annoying.  Have to call the company to see if they'll send a replacement.  TDS tester works great, and I've not experienced the fishy  smell others have written about.  Hope they can find a way to make the filter smaller but still effective because it takes up quite a bit of pitcher space and we have to refill it often.