I am not a specialist and I do not know all the shaving soap on the market. This test has only a relative value. So here is the result of my comparison.
The Monsavon comes in a plastic bowl with a lid (not very ecological I grant you) to 1.05. The soap is soft 125g and has a pleasant smell that reminds a little lemon grass (without being really). The one I usually use takes the form of a hard soap lanolin 120g with a very pleasant smell (reminiscent of the era of barbers) and carefully packed in a paper (like the old) at a cost of around 6. It can also be found in a wooden bowl of oak or beech with lid for about 16.
At the foam, although there is little difference, I will give a slight advantage to Monsavon.
As for shaving: equality at the beard but net benefit Monsavon on the skull.
As for irritations, although having little with the one I usually use, I have hardly any more with Monsavon. Moreover, we feel very well the difference when applying aftershave.
Finally, the Monsavon big winner in this comparison. There remains only the duration. With one of the great British brand, I was more than a year by using it for the beard and skull. The Monsavon is more flexible and may last as long. But even if it takes me two or three a year, I will always win largely on price.
All that crap to say I highly recommend this shaving soap.