I can't comment on the Laney GH series, but I have had great results from my LH50R with a Matamp cab loaded with 4 x celestion GT12 - 75 speakers.
I gather this is the same speaker configeration as the Marshal 1960A cab.
As I play mostly blues & clean, I needed a Laney with a clean channel that could do reverb and retro, but when I first kicked on the hot channel WOW ! what a hot beast leapt out !
For the price they are amazing...
:D
