It's only 20% of the base price. If you end up specc'ing the machine higher (which many ppl do), the % decreases making it a bit better...
Also FWIW, while I'm generally a believer that getting extended warranties from most companies are not worth it, if it's ever worth it, I think it's with AppleCare+. Partially because of difficulty / cost of repairs (which others have noted). But also because in my experience, Apple and AppleCare+ differs from almost every other Company's extended warranty program, where they're trying to find a way to DENY your claim. In my experience, Apple goes out of their way for their AppleCare+ customers to find a way to APPROVE your claim. As long as you're reasonable and don't treat the Apple employee terribly / give them a reason not to help you, I've found they're extremely generous and want to find a way to approve claims.
It's not for everyone (definitely can't make a blanket statement that everyone should get it). And there are many small factors along the edges that may nudge one way or the other (% cost of new price, likelihood there might be an issue (Eg. Gen 1 of new design), total $ cost of a repair and whether that would really hurt your finances, your mental temperament and potential peace of mind / less stress of having it and knowing you're covered for a big expense, how clumsy you are, whether the device is mostly just used at home or you commute with it frequently, whether you have little kids / pets who might damage vs you live alone / all-adult household, etc.)