What do you think makes a good SaaS product experience?

A responsive team who is eager for feedback. Also when your feedback is considered for improvement on an product

UX is usually what makes or breaks your chances of converting a news user within seconds of signing up.

IMO User-friendly interface, to have a clear value proposition (even if it changes to have it clear always) and regular updates or improvements been done

A good Saas product experience is something that is as close as possible to well-designed consumer apps. Unfortunately, very few people working on SaaS products understand this resulting in extremely complex UX and bad visual design. It has gotten a lot better in recent years, as more consumer designers have entered the field, but still has a very long way to go. I understand that SaaS products are inherently more complex than consumer apps (due to the complex nature of some niche industries) but if your product requires an intensive month-long course to onboard either customers or your own employees it means your UI is extremely confusing.

Onboarding system and supportive team that values you as their customer.

UX for sure