When you put your home on the market the traditional way you start out with a big to-do list: fixing it up, scheduling inspections, arranging open-houses etc. When you sell to a cash buyer/investor you're really saying I don't have time for all that - I just need to cash out of this property fast.
OK, but what about the down-side? Yes, you're probably going to get the highest price by selling "retail", i.e. putting it on the MLS and going the traditional time-consuming route with a Realtor.
Investors make their money buy fixing and reselling the property. Realtors make their money by collecting a commission. There's a time and place for both of these. If you need the maximum "retail" price, the best route is to put your house in top condition and list it with a real estate agency.
What about iBuyers? Recently big companies like Zillow and Open-door have gotten into the act of expedited cash home buying. Their claim is they offer the best cash price available. The catch seems to be the limits on what they will buy. iBuyers may exclude properties that are not withing preferred cities, outside a certain price-range, or that require extensive repairs. Some investors have called what iBuyers do a "cherry picking".
*Notes:
Time to sell and closing costs per Zillow:
https://www.zillow.com/sellers-guide/average-time-to-sell-a-house/
https://www.zillow.com/sellers-guide/closing-costs-for-sellers/
Exact details can vary depending on individual agreements.
