Talking about software, this watch runs on Samsungs proprietary Tizen OS, which I've always preferred to Googles Wear OS in terms of responsiveness and general user experience. But just like Wear OS, Samsung hasn't really upgraded Tizen in a long time, so the software has now started to feel a little bit stagnant.
Also, third-party app support still isn't all that great as you have to rely on the Galaxy Store for all your downloads. Overall app selection pales in comparison to Wear OS and Apple Watch devices. On the plus side, the Galaxy Watch 3 offers a great amount of personalization options. There are over 80,000 downloadable Watch Faces available on the Galaxy store and a lot of them are free.