need 30-60x.. think they say "60" but you can only focus at about 30x on the cheapies, which is enough.
basically pay more for better pics and/or larger field of view. i have a cheapie, they work great for their minimal function.. focus on the bract and pistil trichomes... (gah, i said calyx again on another post! stigma comes out of pistil)
i like watching how they progress per strain i clone. still useful to get familiar with even if you grow new stuff all the time. plus, rarely know when harvest is, unless you are cloning and it isn't the first iteration.