After reading all the reviews, I was a little skeptical about buying this.
Not going to lie: the crumb catcher fell apart the moment it came out of the box. The little wooden slats are very fragile and come off easily. We glued it back together. No big deal.
I could TOTALLY see how someone would give this a bad review. I can't imagine cutting bread in this with a manual knife. It would be difficult to line everything up and hold the bread straight simultaneously.
If you have an electric knife, this contraption works very well. I bought it at the same time I bought my Cuisinart Knife. If you line the knife up well, you get consistent slices from even the grainiest breads. Really, all you probably need is an electric knife and you'll get uniform slices from your bread without this slicer.
The major thing I don't like about it is that it takes up a lot of cupboard space. I'm sure one day it'll end up in the back of my cupboard, forgotten.