I've read several reviews where people complain about it leaking. I think it's because the unit isn't located high enough above the water line. I've purchased 2 of these in the last 4 years (2 different houses - not because 1 broke) and it took me awhile to figure this out. If water is spewing out of the venturi, it's because there isn't enough downward pressure to move the water out of the unit fast enough, so it backs up and comes out that spout. Same goes for if the lid is leaking. It's because too much water is building up inside the unit. So try placing the unit up higher, and make sure your pump doesn't exceed 550 gallons per hour. This filter keeps the water clear. The replacement pads are reasonably priced and last a good amount of time. The only thing I don't like is that the replacement pads come as a set - 1 blue and 1 gray. The blue pad is plastic-y and lasts forever. The finer gray one, however, wears out quickly and turns to mush. But you have to buy both just to get the one you really need. But no biggie, it's still a very good filter.

I got this to replace an older model and so far it works great. It required nothing to change so I could just set it up and plug it into my existing tubing. the best part is it came with everything it needs, but I have yet to clean it yet, so we'll see then.

I am still using my old Bio filter. I learned that if I use a lower power filter in the water and a light filter the pond comes out very clear. I am keeping the new bio filter as a backup. I thought I needed a new bio filter but the old one is fine.

This arrived by mail Monday. (we ordered it Saturday!). Installed it yesterday afternoon. The instructions were much better than a lot are. The tubing needed was standard size and there's an Ace hardware just up the road from us. After reading some of the reviews for this product and other products it appears that some of the poor ratings are a result of failure to read, both product description and instructions.
Update:
When we first set this up we used the universal fitting to the top of the filter but the lid leaked a little and the return tended to surge a bit. After replacing it with the venturi tee the lid no longer leaked and the return flow was constant. So far I'm quite satisfied with the product.
For what it's worth no where in the product info does it state that a pump is included. The flow specs are also very plainly stated.

Nice filter. Easy to maintain. Does a good job. It would be nice if the label came off more easily, so it is not so noticeable in the yard.