Only because it's more potent. It doesn't last as long (~2-4 hours) and WD effects are amplified but shorter lived. The high is not similar to heroin in the sense of the warm and pleasant body high and strong nod. Fentanyl in my experience is a cold wave, it dulls pain very well but the pleasant/euphoric feelings are absent. IV fentanyl vials untampered from hospital.

Fentanyl powder seized by a sheriff.[69] Illicit use of pharmaceutical fentanyl and its analogues first appeared in the mid-1970s in the medical community and continues in the present. United States authorities classify fentanyl as a narcotic and an opioid. To date, more than 12 different analogues of fentanyl have been produced clandestinely and identified in the U.S. drug traffic. The biological effects of the fentanyl analogues are similar to those of heroin, with the exception that many users report a noticeably less euphoric "high" associated with the drug and stronger sedative and analgesic effects.[citation needed]

https://en.m.wikipedia.org/wiki/Fentanyl#Pharmacology

You can read all about people's experiences on Erowid and other places as well. Yes, it is a very powerful drug. No, I don't think it's a worthwhile drug to abuse unless you have some incredibly consistent access. It's heavily used in surgery because of its short Half-Life and potency. Yes, I think it is over-prescribed. History repeating itself with what happened to Oxycontin in the US. It's cheaper and less labor intensive to manufacture than heroin so it's a great cut agent. It's not some boogieman super drug though.