Sounds like you found a good deal on my favorite style cab! Is it the oversized or the traditional cab?
I like the traditional more because it seems a good bit tighter than the oversized. The difference I hear between the straight and slant cabs are just that the slant will be firing up into the area of your head which will make it easier to hear the high end and upper mid content and that should help getting a better sound. There shouldn’t be much difference if any between a straight/slant and a slant.
Hope that helps.