I switched from the Pebble Time Round to the ASUS ZenWatch 3 and am quite happy with it. It is a very attractive looking steel watch with three buttons and is not too thick (the PTR is 7.6mm and the ZW3 is 10.8mm). I had first looked at the TicWatch e, but could not warm to the cheap looking plastic appearance and the very thick casing (13mm).
The battery life is similar to the PTR, yet with a much larger full colour screen. It uses Android Wear 2 and that means you have a wide range of apps and watchfaces to choose from.
Like the PTR, it does not have built-in GPS (uses phone’s GPS) or heart rate monitor, yet does have high speed charging. Fully charges from empty in an hour and that lasts me the full day. I just charge it overnight.
It is larger than the PTR, but so is the screen. I found the PTR screen to be a little too small where small text was hard to read. The ZW3 is much better. In bright sunlight, it is still readable when the screen is fully on (always-on is too dim in that case) - not as good as the e-Ink of the PTR in bright sunlight. But I spend most of the day indoors and there, the ZW3 is excellent.
I managed to get mine on Amazon for 145 Euros during a Christmas special offer. Well worth the price.
i have basically already stopped using my PTR in favour of the ZW3 and am no longer looking back.