I agree with Robert mostly, but just a few other observations and vintages:
2011 - mostly quite lean, with one or two exceptions (Clos de L’Echo by Couly Dutheil springs to mind - overripe and syrupy)
2012 - much the same as most 2011s, some crisp, acidic wines which lack a little ripeness, but great if you enjoy the leaner type of CF.
2013 - one or two wines are OK (eg Chevalerie Grand Mont) but really, this is a vintage to avoid - mostly green, unripe and a poor QPR.
2014 - a classic for Loire geeks, it has the ripeness lacking in the previous three, but not as much as the 2015.
2015 - ripe, but not excessively so and well worth looking at, it’s a good long-term bet
2016 - similar to 2014, perhaps slightly riper, very promising
2017 - again, similar to 2014 and 2016 but the wines I have tried so far are just a smidgen riper than in 2016. Wines from some producers, like Yannick Amirault, are exceptional. It’s a vintage I’m still loading up on since the prices remain low.
2018 - as Robert says, this is riper than 2015 and of course 2014, 2016 and 2017. I agree that it is best to stick to the top names - the wines I have tried from Roches-Neuves or Baudry have been breath-takingly good but there are some gloopy wines from others.
2019 - I’ve only tried three wines so far but my initial impression is that this is slightly less exuberant than 2018.
One important thing to watch is the alcohol levels, especially in the riper vintages, but overall, since 2014 there has never been a better time to buy Loire reds.