I would get the Fountain first. During these monster hunts it can drop a Gold Troll Token. It's random, but around once every 3 or 4 collections. (4,5 hour timer)
The Mythic Research Center is the absolute best thing ever, BUT you need Gold Troll Tokens for everything. So even if you prioritize that, you won't have Gold Troll Tokens left to buy anything.
In the end you will want both (their both just to good), and the Fountain potentially gives you Gold Troll Tokens while you save up for the Mythic Research Center. The Mythic Research Center does not give anything while you save up for the Fountain.
But there are cheap animals in the MRC, so if you're in a hurry to (for example) buy a Glimmer Manticore (for 1 Gold Toll Token, 5 Sword Tokens and 25 silver) go for it.
Thank you, that's really helpful. Not having the mythic research centre makes it difficult to know what you need for crafting. Fab thank you :0))