ive got both a 5150 straight and 5150 slant cabinet.
also owned a JCM800 lead series slant cabinet all at the same time, and i have access to another 5150 straight cabinet that a friend uses/owns
straight cabinet whoops ass on the marshall cabinet IMHO. what people say about the straight cabinet sounding "boxy" is correct - but that cabinet retains low end like no other cabinet i have ever played through. if the speakers are not your thing - change them out. but as far as the cabinet goes - nothing short of amazing.
the slant cabinet tone cuts like a knife. sometimes i use both cabinets, sometimes i use only the straight cabinet. i find myself using the straight cabinet more than the slant though.
but i will tell you that i will always keep a 5150 straight cabinet in my possession. if i ever had to sell the slant cabinet i would - even with its very very early serial number. i like a solid low end, not a muffy or boomy low end, or excessive amounts of low end. but i like the punch factor, and 5150 straight cabinets do it at a price no other cabinet can deliver.
all 5150 cabinets are underrated. you will always find more slants on ebay than straights. people who have them dont want to let them go.
i will say that another cabinet worth looking into is splawn's. great build quality is an understatement - his cabinets are amazing for the price. the small blocks he designs sound nothing short of awsome. someday i wish to own 3 splawn cabinets - two with his small blocks and one with celestion V30's
