Let's just clear some stuff up here a sec- I've been growing mushrooms over ten years- all my activity for the most part on reddit is on /r/Shrooms, /r/Shroomers and /r/Mushroomgrowers- I don't know why I felt it necessary to say that, just some small credibility I guess. There's different "strains" of psilocybe cubensis- most of which are more or less the same. Penis envy being somewhat of an exception. But for the most part the PDW of the total alkaloids of P. cubensis is ~1%. These are the most commonly grown/bought magic mushrooms in North America. In the UK, you may end up with Psilocybe semilanceata- or "liberty caps". These also can be found in some parts of North America but are less common. They are different species of mushrooms. I grow P. cubensis and Panaeolus cambodginiesis- the latter is twice the potency of the cubensis. There are also Panaeolus cyanescens, Psilocybe cyanescens and Psilocybe azurescen and a whole host of other species of psilocybin mushrooms. These can be a lot stronger in potency. You should have some idea of what species you're taking because three grams of cubensis is a lot easier to handle than three grams of azurescen. Although these other species are more difficult to come across in the usual drug dealer type situation.

The point that I'm making (that no one will notice probably) is that mushrooms aren't weed- these varieties of P. Cubensis like "Golden teacher" and "Cambodian" and "B+" etc.- they're simply different variations of the same species. They aren't much different in terms of potency variation. Dealers will say "this is a really strong strain" and it's meaningless. Dealer hype. Then there's the fact that the trip is so subjective and dependent on so many variables that it's impossible to say whether it's the mushrooms or the person. Sorry for the ramble.

TL;DR- there's a difference between "strains" and species. Cubes are cubes, and most likely, you've got cubes ---- unless you don't and have some other species, and that's where at least some of the confusion starts. Then there's truffles. And then there's Amanita muscaria (which are also psychoactive, but not psilocybin-containing- they have muscimol). It's confusing.