I always felt that the NX-01 was the ugliest Enterprise. Not because it looks like an upside-down/smushed Akira, but because it does not comfortably fit the design lineage of other Federation ships.
Mind you, in real life, cars in the 70s and 80s looked more primitive than those of the 40s and 50s. Go figure !
Although I do like NX-01, I think the Conestoga would've been a better design for that era.