Darex M2 vs Darex SP2500

I cleaned the crud off of the Darex sharpener that followed me home today. To say that it was dirty would be to say nothing. All that stuff lived in a grinding shop, sat on a shelf, and has years of sediment accumulating.

Anyway, after cleaning, it turned out to be a model SP2500. Looks very much like this:

Currently I have a Darex M2:

My question is, which one is better for general purpose hobby use. I want to keep the better one and dump the less good one.

thanks

i