I'm a big yerba mate drinker (at least 2 cups a day, everyday) and while Adagio's sampler was good, it wasn't the best I've had. Teavana, on the other hand, can have some tasty blends, but they often load in a lot of extraneous fillers to pad out the tea. Coupled with their already high prices, the value proposition is just totally out of whack.
As for the differences between Adagio's and Teavana's yerba mates: Adagio is selling a few different varieties of mate, which are processed in 1 of 2 ways. The plain yerba mate, citrus mate, and mango mate all use "green" yerba mate, which can be as minimally processed as only being allowed to dry, or as processed as being smoked. Minimally processed yerba mate is more popular in Brazil. Smoked is more popular in Argentina.
Adagio's toasted mate, spiced mate, and mocha nut mate all use "toasted" or "roasted" mate. I believe the difference between the terms "toasted" and "roasted" is just marketing, but I'd argue that "roasted" is probably the more apt descriptor. Roasted mate is cooked in a similar way to black tea to achieve a dark brown or sometimes black color. The effect is that roasted mate takes on notes of chocolate, instead of green mate's herb-y flavor.
Teavana uses roasted mate in its My Morning Mate and Matevana blends, so it is fair to compare those two to Adagio's toasted, spiced and mocha nut flavors. Teavana uses green mate in its Raspberry Lemon Riot blend and used to offer green mate at its stores. It isn't really fair to compare the Raspberry lemon riot blend as there is very little yerba mate in the mix.
My go-to green yerba mate is Mate Factor (http://matefactor.com
). It isn't processed in the same way as Adagio's plain mate, which is something closer to an Argentinian style (though it is apparently produced in Brazil). The cut of the tea is also very different.
My go-to roasted/toasted yerba mate is from Upton Tea (http://uptontea.com/shopcart/item.asp?f ... temID=BH22