Here's my tiered list of most popular brands (models) best to worst...
Leopold, Ducky, Filco
Noppoo
CM QFR/XT, Rosewill RK9000, Keycool, Steelseries (though I generally would avoid them because of the dumb enter key they are well made)
Cherry, Vortex
iOne (Razer BW, qPad, CM Pro, Tesoro, Max, etc...)