I bought the EFU-35 about a year ago, and it works great. The UV bulb recently burnt out, but my lfs carries them, so it's not a problem. It is on a 55 Gal. I have 1 liter of Seachem Matrix, 2 100 mL Purigen pouches, polyfill, and the coarse sponge that it comes with, and my water stays crystal clear. It has a much larger capacity than the Fluval 304 that I used before it.
I haven't had any leaks, and it runs very quietly. Some will say that it is a bad idea to have UV built into the canister, but with the way this one is built, I don't see how anything could go wrong.
For the price, it is an excellent filter.