I have the 304-b. The flow is actually pretty good on it. So far nothing has leaked and the only part I don't like is it takes some muscle to get it going. However, I rarely have to do that so it's no big deal. As far as media, I haven't been very adventurous and just stuck with the standard media with bio balls and it's been doing great. If you plan on just using filter pads then it will definitely clear up your water. I saw one on ebay the other day for $87 shipped which is a steal and a half due to the enormous amount of room there is for the filter pads. Oh and the UV doesn't last very long if you care about that.