I've had this GW7 for about two weeks now, upgrading from the GW4 (which has been fantastic since day 1). The interface is really nice and smooth and fluid, and it's clear there's been a lot of work done with Wear OS in the past couple of years. If you've previously owned and loved a Samsung watch, this one will only grow that love even more.
The device itself is mostly physically unchanged from the previous non-Classic or Ultra models, and your old watch bands (20mm) will fit the 7, as well as a few of the cases. It feels like it weighs the same and definitely fits the same as previous models, so you know it's comfortable when worn.
The updated Wear OS 5 with OneUI 6 is great. It feels snappy and by and large it looks much the same as previous versions, with the exception of a vastly-updated PIN unlock screen. Suffice to say that the software is maturing very well under Samsung and Google's combined efforts.
I don't use a Samsung phone so there are a few features I don't get access to. Primarily it's the AI features that I lack exposure to. Typically the Blood Pressure and ECG functions wouldn't be supported, either, but there is a pretty simple way around that if you have a Pixel or other non-Samsung phone.
Charging this device seems to take just as long as previous models, so there's not a lot of advancement in this category. The charger puck now comes with a USB-C connection rather than the USB-A from the days of old.
There are a lot of reasons that I am glad I upgraded, and with a great deal, I feel like I got a stellar watch and experience.