The 1st question, what do I intend to make or resharpen?
2nd, Which machine is the easiest to use for what I want to make?
For myself, the Deckel type will make the form cutters etc for what I need, like internal or external special threading tools, or single point D bit type cutters of many geometries etc.
The little Clarkson's are a very capable machine and there is a huge range of accessories .It then becomes a learning curve all be it a very satisfying one, learning to make various cutters or regrinding them etc. Diamond or cbn wheels allows many things to be done as well in carbide or HSS or stellite etc
If you have the room etc for the Clarkson, I would recommend the Clarkson, but that's because I have used one years ago and enjoyed making things on it that were not available at the time.
If space is a problem, and you only need single point cutters or basic geometry single lip cutters, etc then I would recommend going the Deckel clone route. I do like the D bit grinders alot, and it is really nice if you can have both machines.