Just treated myself to one of them there new fangled
Apple Watch 4's to replace my first generation model. I really just wanted a waterproof model so I could go swimming had have some music in my ears. Nearly bought a used Series 2 but ended up going all out becuase I'm daft.
Going from the first gen to this... Siri is way quicker. First gen would take a good 5-10 seconds to analyse what you said and get a response where on this model its just as fast as on the phone. Everything is way snappier, apps load up quick, menus never hitch (though it was rarely a problem before) and music populates instantly. The battery is much better getting me the best part of two days versus the originals low battery warning at every bed time. I also really like the autosync of podcasts to the watch. The new screen is very nice and if anything I think it might be a touch too big now but not overly so. Apparently the smaller model has more active screen area than the large model of the previous watches so the small one might be the one to go for.
All that aside its kind of not worth the upgrade from even the first gen one beyond waterproofing. I mean, a few seconds extra on siri and slightly slower response isnt a deal breaker nor is the battery lasting the whole day. Its fairly incremental and the first gen one is still a great watch.
Now what I
really like though is this e-sim shit! I absolutely love that I can just leave my phone at home and I have most of the communication functionality on the watch. Maps/phonecalls/texts/music/podcasts etc.. all the major stuff is right on my wrist no matter how far away my phone is. Even email kind of works though its a bit fiddley. Theres a perfectly usable twitter client and skyguide even works on the bloody thing, AR mode and all! The majority of this stuff does work on the Series 3 through which I would probably have went for instead knowing everything I know now. Its not without some irritants but overall this is a step towards what I have always hoped will be a thing where your watch is the brain of your phone and you just have a series of slave screens of whatever size (from 4" to 12"+) that all run off the same brains.
A bit of a downer is the ECG stuff doesnt work outside of America for the foreseeable future. So no detecting my defective heart

A man who could tell more truth and eat fewer pies.