Upgraded my Apple Watch Series 3 (42mm) to a Series 7 (41mm) this past week and I'm pretty satisfied. It is much faster and because of the larger screen it feels bigger even though it has a 1mm smaller enclosure. The always-on display is great too.
I purchased the cellular model this time around and I love how smart it is with having cellular radio turned-off when in proximity to my phone and turns on when I leave my phone behind.
I honestly wish I could just have the watch without the phone.