Nice and clean.

My daughter's college bike is also a UO-8, with the original Simplex Prestige plastic derailleurs. They work fine, until they crack, which might be tomorrow or never. So keep them lubed (the plunger that slides in and out of the front derailleur especially), periodically apply some Armor All or other plastic-vinyl protector, don't over-tighten the front derailleur's mounting screws, and worry about replacing them when they actually need replacing.

The rear derailleurs held up better than the fronts. Your bike looks barely used - freewheel teeth show little wear - and I'd clean up the rear derailleur then start troubleshooting. It probably just needs an adjustment, unless you see an actual break or crack in the plastic.