UPS are actually great for sensitive electronics. The power in your home isn't as steady as one would wish, and a UPS cleans that up before sending it on to your devices. It's kinda like driving a car down a smooth road instead of a rough one. They also protect from surges and, of course, provide some power after the lights go out! I love em, but they're expensive compared to a surge protector.
Whole house surge protectors can protect against large surges coming from outside your house but they don't really do much for the more common smaller surges that pop your electronics or originate on the same circuit. Putting a decently rated surge protector on any expensive electronics is definitely still worth it.
I'm surprised your AC unit would go bad from a power surge, it takes a pretty big spike to take those down.