I've had zero problems making lather with MWF. I've shredded it, like Glen with good results or left it intact with equally good results.

I posted this in an earlier thread about MWF, and this is what I've found to work for me.

1) Soaking washes the lanolin out of the soap over time. That's why my first puck turned into a brick.

2) The right amount of water that makes good lather for each type of water (hard, soft, etc), is a very narrow window.

3) Temperature makes little difference in the quality of lather. However, very hot water, over 140 F, will break down the lather in a scuttle.