Fentanyl is extremely potent yet dull at the same time, if that makes any sense. It will get you high as hell and cause you to nod out. But take all of that, rip away the warmth of certain Opiates and then make the high only last for 45 minutes at most. That's basically Fent for you. Very potent, very addictive but also very short-acting. As for the euphoria: I don't know about analogues or even the difference between them and regular, pure Fent (With the exception of Carfentanil which I'm sure everyone has heard of due to it's ridiculous potency and dangers) but the Fent that I've had does cause euphoria, just not very long lasting and it lacks a certain aspect of a normal Opiate high which is hard to describe but very noticeable when it's not present.