I enjoyed playing Omega Boost the first 2-3 times through.
I the Stealth plane is not one of the ugliest designs out there, imo, there were plenty of real world airplane designs from WWII through the '70s that were amazingly ugly.
The Stealth plane was built for a popcorn flick, big explosions and summer fun. It was NOT made to be accurate, it was NOT made to please the armchair military analyst, it was built to look cool going a million miles an hour on the big screen.
I have a feeling the only reason most people here slam it is because a few people complained "omg, that thing would never fly, the angle of the (insert random tech jargon here) is all wrong!". Seriously, is was never made to be a real world design in any way.
As for the rest of the movie, yeah, it was poo.
Here are my submissions for ugly Mecha: