So I've spent some time with both. They are different, so it's not really fair to compare them.
Bogner: more middy, louder (if volume unchanged), more high-end detail. Can get gritty/grainy so yo have to dial that out. More 'in-your-face' which is probably a combo of the speakers and amp design.
Friedman: more depth, punch, tighter, bigger at lower levels, can crank up the amp and highs a little more.
No matter what speakers you put in these cabs, the I believe the characteristic differences will be the same. It's physics. Look at the differences in dimensions.
You cannot go wrong with either. I did end up using the Friedman at my gig this past weekend and was very pleased with it. The ONLY complaint I have is the V30s are not broken in. I think right now I lean toward the Friedman. ...And I JUST received the back panels for the Bogner (From Bogner) so I have two totally badass 2x12's. ...Now, if I can just get my hands on a Stone Age C. Ha!
Also, I plan to unsolder and add size 12 AWG .205 terminals so that I can swap speakers as I wish. I did this with my Bogner OS and it works perfectly. I don't know why most cab makers use the .250" terminals; they are not tight enough. I would like to mix either a CBH75 or 65 with the V30 in the Friedman. ...Maybe even a Redback for total destruction.
You do not need to solder speakers if you use .205" terminals for Celestion or Scumback speakers; those will be very snug. Highly recommend if you are not keen to solder like me.