Sorry if its derailing the thread to have the grinder conversation again... would be really nice if there were a MFLB subforum instead of just a thread.
To answer the question: I've been using the Mendo Mulcher almost exclusively since getting the LB 6-7 months ago. Nearly daily use though I do use an SSV too. I use the same grind for both of them. I use the MFLB tiny grinder on occasion and it works pretty well, but its hard to twist since its so small and lacks knurls on the bottom piece. Have to say though that I am very impressed with its quality - its totally usable for a modest user and eliminates the need to purchase a better grinder. Needless to say though, some of us "power users" want a little less labor in using the box. To that end, I just used the MM which I already had for the SSV, and no complaints really. I have the 3-piece to catch kief but knowing what I know now, I would get a 2 piece. I use it sortof like a 2-piece by holding it on its side or upside down to regrind as much as possible.
It creates a grind a little finer or very similar to the micro-grinder MF included.
The coffee grinder (ubiquitous $14 unit - might be Mr Coffee brand) does a much rougher cut, even when allowed to go for a long time. I've been trained not to run those things for more than 15 seconds to keep the motor from being prematurely damaged, but I ran it for about 45 just to see what it would do. It wasn't really any finer than it was at 15 seconds. The thing really seems to whip the trichs into orbit though... a cloud of hash dust emerges when you upcap it and a decent yellowish deposit of golden mist is all over the formerly-clear window. Maybe the grinder is coated like this too and its harder to see since its not clear, but I don't think so... For me thats 2 strikes against it.
I probably should have known to not fix what ain't broke, but I saw the grinder today on a minor sale and seemed to recall it was the preferred choice for MFLB users.
I would expect that all the common high-grade grinders are decent and its aesthetics and personal preference between them. My nitpicks of the MM are that the threads can get clogged with kief pretty easily, and sometimes an especially sticky flower section will get stuck in the center where there is no tooth. Some people say its better for joints than vapes, but it seems fine to me... certainly works!