I just started up my Proffessionel 3 this weekend. I have 180 gal. And I think it´s doing great job, easy to prime and setup. It has a very strong outflow and the tank has plenty of movement in it. the only flaw I is the green hoses and tubes. It does not look good in the tank (really stands out ) and the connection possibillities are limited. I think the tubes on the RENA xP are much better. But part from that the filter works great. It´s a bit louder than the pro II wich I have in another tank, but It´s not a big deal just a low heavy sound. Anyway I wasn´t expecting such a large filter to be dead silent.
I would recomend this to anyone, but it costs alot. It´s cheaper to buy 2 pro II, but I think it´s easier to maintain if you have one filter rather than 2 on one tank.
I don´t know why Eheim has these cheesy hoses and tubes, I would rather have black or gray tubes and clear hosees. Mabye I will replace them later with some that are more attractive in the tank.
This filter gets 9.5 out of 10. It looses half point because of the hoses and tubes.
One other thing!! This filter takes a lot of space, so you have to have plenty of space in your cabinets, needs to be rather high.