For the prices you’re quoting and the system cannibalization issue, I'd go with HP. We have been using them for several years and canning old systems for Hard drives and memory. We don't usually use dedicated GPU's for desktop publishing/ data entry, which is what the majority of our users do.
If any users needed CAD (we have system architects that do) we got them stock D400 or D800 workstations. But I am limited to what’s on GSA.