Roofstock is a marketplace: vetted, often tenant-occupied single-family rentals you can buy end to end. A marketplace completes when you transact — which is why the number it can never hand you is "walk away above $X." ReInvestIQ has no inventory to move. Bring any property — Roofstock listing or otherwise — and it returns an independent, data-grounded verdict with a computed maximum offer and a stress test behind it. Here is the side by side. An independent second opinion with a number attached: a computed maximum offer, multi-source rent validation, and a verdict that is free to say NO_GO.