Another SaaS benefit that isn’t readily apparent before going live is the relationship between quick product enhancements and reference customers. Because you can update and enhance the product so fast, customers that make small requests can see the changes within a matter of days or weeks (assuming you accept the tweak and it fits in your opinionated vision!). This goes a long way towards having them become a reference account that you can use for future prospects. With installed software, it is difficult and time consuming to keep making little patches so customers often have to wait several months for the release cycle to happen before they can actually appreciate that your team has been working hard on their request.
Near instant gratification with product change requests is something many clients have never experienced. Please make sure and temper expectations that it won’t always happen but that you’ll always be there to hear them out and be understanding.
David Cummings on Startups 