http://www.procooling.com/html/pro_testing.php
look at the wbs that can be purchased, and also at their respective cost
#1 DD and Swiftech are
not equal (the Dtek WW would have been a more appropriate comparison)
#2 the G4 is clearly better, but there are reasons why such a design may not be suitable for the 'mass market'
#3 a DIY wb WILL be inferior to the MCW6000 (anyone who thinks not, send your wb to pH), despite what is said by wannabes
in short your entire premise is flawed, the best wbs are made by one individual in limited quantities at almost twice the price of the 2ed best wb which has lower maintenance and pump requirements
does not seem too complicated to me