If you mean the slicer by Zivic Instruments, I would suggest you avoid it. We purchased the young rat slicer from them in September, and only after 6+ phone calls was it sent (received it yesterday) - and it was defective (the slicing channels were all slightly bent toward one direction). Ted Pella has some that look pretty sturdy, though I do not recall if they have an adolescent one.
Never used Brain Slicer Matrix brand. But we have several Leica VT 1200S series for a number of years and they are pretty good for cutting adult brains, as they allow setting and minimizing the vibration amplitude. I and many others have been using them in from embryonic to very old animals (mice and rats), and we are happy with its performance, good and healthy slices for ~6 hours. However, you will have to calibrate it pretty much everyday prior to use, if you choose to use standard blades.
If you mean the slicer by Zivic Instruments, I would suggest you avoid it. We purchased the young rat slicer from them in September, and only after 6+ phone calls was it sent (received it yesterday) - and it was defective (the slicing channels were all slightly bent toward one direction). Ted Pella has some that look pretty sturdy, though I do not recall if they have an adolescent one.