Well i had the Hydor 4's before i upgraded and it really made alot more room adding the Vortech's vs the Hydor's...I had an issue with one knocking last week and the bearing had seized up two days later i had parts sitting at the front door no questions asked....great customer service....I now have an MP40w gen2 and a MP20...but i am gonna be in the process of upgrading the 20 to a 40 here in the next couple of months...don't really need it now b/c i only have a 75rr but the next tank will be bare bottom and larger so wont hurt anything