The MEGA 'Weiler is a better slicer, hands down, no contest. Thinner immediately behind the edge, and most of the way up the blade.
This will probably surprise most folks, it's as close to neutrally-handling as you can really get; with the thick stock, there's enough meat in the handle section that the balance point is right at the very front edge of the handle scales on my black canvas example.
So while the Rat doesn't handle like most choppers, the weight of the blade is there when you do chop with it, and the hybrid grind helps it bite quite deep for it's size.
On the other hand, the HOGB8, being Res-C, flat ground, and a milled stick tang, has a much, much more forward balance point. Much more like a dedicated chopper. The thicker edge has a lot more weight behind it too, and so while it bites fairly similarly, it sticks in the cut more than the MEGA Rat does. Very dissimilar geometries accomplishing the same thing in a much different way. I'd have to say that the Rat is the better all-around knife if I had to choose one for that task. Granted, it's SR-101 vs. INFI.