The one with the most leaves looks fine, it just looks like its autumning. The one without so many leaves doesn't look quite so good, with a lot of leaf loss towards the top.
Mature plants need particular care for at least two years after planting, because it takes them much longer to settle down and start growing in their new environment, so copious amounts of water are required whenever the weather is dry and especially if it's hot. It may be that the one with fewer leaves didn't get quite enough water throughout the summer so its lost more leaves early - the other possibility is, it's more exposed to the temperature and elements at the top, which would also cause earlier leaf loss there if the temperatures have been low, particularly overnight. The worst possibility is dieback, but you'll know if its that by next year, the twigs at the top won't leaf out in spring; dieback cannot be treated nor prevented in most cases, and Acers are prone to dieback.