Ok, so you want to be a Magento Master: you'll know (almost) everything there's to know about the system and you'll try to convince everyone to use it. Great!
But don't confuse that with being a sales representative for a Magento company trying to make as many sales as possible. You are enthusiastic about the system, but also be realistic and a critique. I think Magento in general is probably the best e-commerce platform out there. But that doesn't mean it's a miracle system that is going to sell stuff by itself and it's not the perfect system (mostly because I think perfect doesn't exist with software). It also won't be the best choice for every businesses. So there will be bugs, faults and strange things you and users will encounter and need to deal with, just as with any other software package. Tell them about that openly and up-front, tell them what they can do about it and they'll be much happier users. There's no use in 'selling' Magento to people who won't be happy using it. For example: The way Magento is build makes it a real resource hog. Great when you want many features, great when you're a developer that wants to extend the system. Not so great when you're on a slow server and like speedy webshop performance. Luckily, there are many, many things you can do to counter that problem by using (one or more) fast dedicated servers run by a hosting company specialized in Magento. (Also see my blogposts 'Magento Performance: Myth vs Reality' and '101 ways to speed up your Magento e-commerce website' on this subject).
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.