You can see comparison images of the three here:<p><a href="https:&#x2F;&#x2F;nest.com&#x2F;support&#x2F;article&#x2F;How-can-I-tell-which-Nest-Learning-Thermostat-I-have" rel="nofollow">https:&#x2F;&#x2F;nest.com&#x2F;support&#x2F;article&#x2F;How-can-I-tell-which-Nest-L...</a><p>They appear to have both reduced the brazel size and increased the display&#x27;s size. Additionally it is a little thinner than the 2nd gen and massively thinner than the 1st gen.<p>Definitely an improvement at the same price point.