I've looked at those Muji products myself, have you used them before? Most of the stuff they sell is pretty decent so I expect those to be quite good.
Ι cannot remember if I have used their cosmetics before.
I know I have used their travel soap bar, but that was ages ago (2006-2009).
I tried these extensively (to the point practically attainable) at the store two days ago, in Singapore.
So I selected the ones more suited for me, as they had the white and also the blue line, each line having 3 different emulsions/lotions...
Having used the likewise 'budget' cosmetic lines from Korean brands since 2006, the first thing that comes to mind is that the approach and setup of using these ones here is kind of the same. Meaning that you have toner, lotion, emulsion.
Somehow the Japanese and Koreans have this philosophy and generally offer three stages/steps in face care, whereas (generally speaking) in Western products you can use a toner (which is light, like water) and then apply your moisturizer. With Korean and Japanese cosmetics this approach changes.
In summary here and depending on what you choose these can be quite 'rich' (meaning oily-like, at least this is how I personally find them at times.
But for the price they are worth a try, I believe (for us here in Greece we have no Muji).
I'll report down the line after using them.
Don't expect them to replace my CF 1445 balm to be honest, but let's see how they perform.