I used this for approximately 3 months before I was frustrated to the point I had to either buy something else or rework this into something usable.  The problem is long knives aren't very good for cutting bread because they flex and wander, and there aren't many long knives out there in stores to be found (as I experienced).  Also the guides are so far apart on this guided cutting block, that the guides easily leave an inch to either side of the loaf.  In my experience you need to hug the loaf to keep it from moving around for a good straight cut (especially when the loaves are warm).  So what I finally had done was to remove the side guides and repositioned them to the inside, screwed them back in at approximately the same height on the sides.  Then I broke off one of the removable tray's glued on wooden pieces, and cut back both wooden support spars that hold the individual wooden tray bars for the crumbs to fall through.  Then I simply used a dremel with cutting wheel to cut off the excess on the removable plastic end piece and filed it down smoothly beveling the edges, placing it back in it's new position.  Now it works great!!

Just for other buyers consideration, the loaves I made are standard size 2 lb ones from a Zojirushi BBCCX20 Bread Machine for which I use Whole Grain Flour.  The knife is the OXO Good Grips 8" Bread Knife (which has an ergonomic round handle with flat edge that buts up flush to the cutting block's guides).
I used this for approximately 3 months before I was frustrated to the point I had to either buy something else or rework this into something usable. The problem is long knives aren't very good for cutting bread because they flex and wander, and there aren't many long knives out there in stores to be found (as I experienced). Also the guides are so far apart on this guided cutting block, that the guides easily leave an inch to either side of the loaf. In my experience you need to hug the loaf to keep it from moving around for a good straight cut (especially when the loaves are warm). So what I finally had done was to remove the side guides and repositioned them to the inside, screwed them back in at approximately the same height on the sides. Then I broke off one of the removable tray's glued on wooden pieces, and cut back both wooden support spars that hold the individual wooden tray bars for the crumbs to fall through. Then I simply used a dremel with cutting wheel to cut off the excess on the removable plastic end piece and filed it down smoothly beveling the edges, placing it back in it's new position. Now it works great!! Just for other buyers consideration, the loaves I made are standard size 2 lb ones from a Zojirushi BBCCX20 Bread Machine for which I use Whole Grain Flour. The knife is the OXO Good Grips 8" Bread Knife (which has an ergonomic round handle with flat edge that buts up flush to the cutting block's guides).