Ive not used the Challenge spoonman, but I understand its adequate for the job. I say that because its often recommended as really the first grinder to consider for ongoing use (bar the Sunbeam which is more a stop-gap unit). It can go finer than necessary and is stepless (I believe) and is built well enough, so is up to the task.
The comment about Silvia being finicky about its grind goes around a lot; personally I think once youve worked out how much to dose to allow for the showerscreen (and I havent had issues on that for months), its no more or less fussy than any other machine with unpressurised baskets at that price point. The cheaper design of the group with no pre-infusion means youre more likely to get channelling which I believe (though stand to be corrected) is what makes it supposedly fussy on the grind. But the same would equally apply to the Botticelli, Lelit / Imat / Quaha / Nemox machines, probably the Isomac Venus and no doubt others.
Unfortunately I think its one of those statements in the espresso world that were made in the dark ages of the internet and are quoted over and over so people think the sheer number of people saying it makes it accurate, when in fact theyre probably all quoting from a few sources who may or may not have been well informed.