Mr. Wilson
Explorer
I'm one of those people who consider the Pally to be among the most powerful classes, if not the single most powerful.
Pretty much everything has been mentioned at this point, but I'd like to point out one thing that has only been hinted at.
Having a Paladin in the party makes the entire party better, and noticeably so. I don't think any other class can have such a huge positive impact on an entire party as the Paladin can. The Cleric is runner up IMO.
Pretty much all of their Auras(spells and features) are REALLY strong. Never worry about failing a save again if you're a pally or standing near one.
I'm jumping back a couple pages, but I'd say that Bards (and especially Lore bards) are the class that has the most positive impact on parties. Being able to snipe the best buff spells across spell lists along with Cutting Words and Bardic Inspiration is more powerful than the aura, IME.
On topic, Paladins are a top tier class, for sure, but they shine best in the type of DnD that most people play, which is 1-2 encounters per session and can unload all their resources.