delericho
Legend
I ended up making a run to the game store, and got myself both, lol. Couldn't decide, so I took option C.
That would have been my recommendation. The adventure in the Starter Set is superb, IMO - probably the single best adventure WotC have published for any edition of the game (but note that that's WotC specifically!). However for everything except the adventure, the Essentials Kit is vastly the superior product, IMO. I'm afraid I wasn't at all impressed with the adventure from that one, though it has some value as side quests for "Lost Mine of Phandelver."
Incidentally, for a while there WotC were giving away PDFs of the Essentials Kit rulebook for free (as part of their pandemic response). I have no idea if that's still available, but if so it's worth grabbing - I thought that was an excellent summary of key rules.
And just for fun, I grabbed an adventure, too. I AGONIZED over the decision of Storm King's Thunder; or Curse of Strahd; or Ghosts of Saltmarsh... They all looked so interesting! I finally went with Storm King.
Ah. Alas, my experience with SKT was not so good. Giants too easily fall into the "big bag of hit points" mould, so it quickly lost interest. Though it does follow on from "Lost Mine" quite well.
IMO CoS is the better adventure (though I haven't read GoS) - until recently it was probably their best 5e storyline. Though I'm now tending towards "Rime of the Frostmaiden" as a new favourite.