i think it varies for everyone and depends what you look for, speed, shine, temperature blah blah...i had some 'hai stik' straighteners for 5 years before ghd's really came onto the market and i swore by them. like you, when they eventually broke i tried to find ghd ones but cheaper. i was always anti ghd until i borrowed my sisters ghd's for a week, and then tried two other brands thats claimed to be as good as them but at less than half the price - i sent both pairs back and i'm currently utterly in love with my ghds :) i got soooo many compliments the first time i used them yet i wear my hair straight everyday!!
anywho, let us know how you get on!!