See, I feel the opposite. I have a Rena XP3 on one tank and an Eheim 2026 on the other. I couldn't be happier with the eheim, but every time I have to deal with the Rena, my whole floor ends up getting wet and the thing sucks air for an hour. Not to mention it has started leaking out of it's power cord, how messed up is that!
I'm trying to talk a guy into selling me an Eheim Pro III for cheap, and if I get it, I'll be ditching the XP3.
I mean, overall the XP3 isn't awful, but it's nothing like my Eheim. Compare the Eheim Classic to the Rena XP, it's a different story, but you really can't compare those two filters anyway.