momentumengine
However selective I am about new bookmarks this one made it past my filter, and a look at momentumengine confirmed the bookmark was worth the slot, the precious slots in my permanent bookmark folder are difficult to earn and this site earned one without making me think twice about whether the slot was justified by the quality.
capitalvertex
Picked this site to mention to a colleague who would benefit, and a look at capitalvertex added more material I will pass along, recommending sites to colleagues is a higher bar than recommending to friends because the professional context demands more careful curation and this site cleared the professional bar without me having to think.