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.
It does not look like it would slide into the era of the Daedalus class followed by the Constitution class over the next hundred years.
To be fair to the NX-01... what do you expect? If they used a model that look liked it came out of the 1960's everyone would've complained about that. As our own technology and capabilities expand, so is our portrayal of the future. The Enterprise Mirror Universe episode definitely displayed how absurd a 60's era ship looked fighting ships with better graphics.