We have the tendency to express undue liking for things merely because of familiarity with them.
Unfamiliar products might be better than the products we are familiar with, but we tend to stick with the familiar because... well... they're familiar. I think this originates in that we expect from ourselves that we started using a product for a good reason. It would be highly inefficient to start doubting that decision every time we encounter an alternative and to learn to use a new product. Mere exposure already triggers this effect. You can use this knowledge to be aware that it helps to expose people to your products (preferably multiple times) to gain an advantage over competing products. You could think about free samples, free trial or starter packages or real life exposers on en expo or conference.
Recently I've seen some (often absolute) statements going around, generally in the line of "open source commerce platforms are a terrible idea". Now of course different solutions always have different pros and cons.
A hierarchy of evidence (or levels of evidence) is a heuristic used to rank the relative strength of results obtained from scientific research. I've created a version of this chart/pyramid applied to CRO which you can see below. It contains the options we have as optimizers and tools and methods we often use to gather data.