I have completed Lost Mines of Phandelvar and Hoard of the Dragon Queen, but neither are options in the poll. Currently playing through Out of the Abyss so I can't really say I've played through it yet.
Well, were still slogging away at Tyranny of Dragons that I brought home from Gen Con 2014. Is been an epic campaign and I'm planning on taking the party all the way to level 20 by continuing the fight to the final showdown with the Queen of Dragons on Avernus.
On the first read the campaign was full of holes, but I've "rolled with the punches" and filled in the gaps as we've played and I must say it's been a beautiful thing! I suspect that this type of broad reaching, epic level 1-20 campaign with factions and politics and armies and intrigue and victories and disappointments has a once in a lifetime experience (and I've been playing for 30 years).
What more can I say!
You could transition to SKT with Blagothkus and his Sky Castle...
That's a perfectly fine idea, but I know my group will definitely want to have closure on the whole Tyranny of Dragons storyline.
Besides, if I'm going to get them wrapped up in another long campaign, I want it to be Curse of Strahd.