I would like to know, what amp from another manufacturer is comparable to the Quality and potencial of the Pass X600 regardles of price. What amp can be consider to be as good as the X600. I'm in the market for a pair of monoblocks, but seems that I won't be able to find any X600 any time soon, so I need another options? Also what make Pass labs X600 so heavy? is it worth the weight?Any help will be apreciated before I make a decision.