I have several Gransfors axes and they are fantastic. They come shaving sharp and, unlike poor quality steel ground like that, they will hold an edge for a substantial period of hard use. The handles are very nice too. The one drawback is that in wet environments, they get a lot of surface corrosion. If you chop regularly, the edge will self-clean. However, you need to be very diligent about cleaning and protecting the sides of the axe head. I doubt the rust would cause any functional problems----it just annoys me!
The sheaths are also excellent quality.
I've looked at the Marbles but haven't cut anything with it. I think the Gransfors would be a more aggressive chopper, based on weight, design, etc. However, I really don't have much basis for that speculation.
When Marbles puts out the safety model with the pivoting edge cover, I'm thinking of buying one just for the heck of it.
DPD.