I had a little Peavey Bravo years ago, it came with a sheffield, nice sounding little amp. I happened to have a vintage 30 laying around so I thought I'd do a swap speakers and honestly I barely noticed a difference between the two.
Marshall 4x12's come with different speakers depending on the model of the cab, I had one with 90 watt sidewiders one with greenbacks and Marshall's are the sound of rock imo.