I think this is hideous. It is striking, but hideous.
I always think the 612 has a kinda dopey-looking face, like the following emoticon
Kind of happy-looking but in a stupid way. Not "plain ugly" though.
Same thing with the 599. The GTO variant makes it much better-looking with the dark front grille.
How about this one for "plain ugly"
Maybe more like simply bland, not "plain ugly", but I expect more from the manufacturer.
Yes, the 1980s are full of boxy cars, but boxy can be pretty. Just see the 308s and 328s for proof.
The 80s and early 90s Mondials are quite literally boxes on wheels. Just that.
And unlike with many other cars, the beautiful setting of that photo doesn't really help either. Combined with the fact that it's shot from above, the blandness is actually emphasized. The coupé would look better with that angle though, I think.
NOTE: I just edited my post - the picture of the Mondial I recently linked to didn't show up.