I also have the MM black one. I love mine, too. Some pros:
It has a magnetic ruler for measuring, if needed.
It folds up for ease of storage.
The blade is self-sharpening. I've had mine for several years and have never had to adjust it, either. I love that I don't have to worry with replacement blades.
Each cut is always sharp and without torn-looking edges.
Some cons, though:
You'll need a different trimmer for cutting very small pieces of paper. I use a Creative Memories little personal trimmer for that.
It's heavy. I use a Fiskars for crops. I like my MM so much better, but it's too heavy to haul with me when I have so much other stuff, too.
To keep the lines straight, you need to be really careful that you line your paper up properly. Of course, that's with most trimmers.