the HW and the SLP doesnt sound the same, I'm NOT sayin' that one is better than the other, only that I think there are some caps in that change the tone (however they are not 2 different worlds its obvious), I think that people have to buy the one that they prefer.. the HW IMHO has a better tone but its very high priced, it gives you also the possibility to mod your amp completely in an easy way.. but in the end its all a matter of what you're searchin' and the money you have... try 'em and choose the best... for who thinks that old ones are better... maybe but I've seen many and I can say that only a 5% where completely stock, the other or have problems or have changes inside.. beware
PS : trannies thoeries are not true