Amazfit’s line of smartwatches may not offer all the bells and whistles of an Apple Watch or Samsung’s Galaxy Watch models, but they do offer incredible value given their competitive price tags. The latest model in Amazfit’s stylish GTR line-up aims to repeat the success of its predecessor, the GTR 3, but with a different approach to design, improvements to tracking , a bigger display and a bigger battery. Are all these changes worth upgrading to a GTR 4, and how well does it work with both Android and iOS smartphones? Read on to find out.