I really wanted to put together some thoughts now that I have had some time with both the 38mm SS BSB and the 42 SS BSB that came in today. There has been much talk in these forums about the aesthetic differences between these two sizes, but I wanted to share some practical differences that may be important as well. In addition, I wanted to list out a couple of useful tips after four days of use. Just a bit of background. I ordered both as I wasn't sure which size would work for me, but I suspected the 38mm would be the winner. When I went for my try on my perspective changed and I instantly decided that the 38mm was too small and feminine looking to me; the 42mm looked perfect, although maybe a tad large (I'm a 175mm wrist for those that think that is important - I don't!). My tryout had a white sports band rather than the black and I think that was a factor as I stated in another post. My 38mm shipped first and I was lucky enough to receive it last Friday. Wore it all weekend and loved it, thought it was a perfect size and now figured that I wouldn't want to switch to the 42mm when it came in. However, I started to notice some practical issues unrelated to how it looked: - I had real problems reading the complications on many of the watch faces. This is partly the size and partly the colors used, but this started to become a real issue. At one point my wife suggested I try her reading glasses. I told her not to be ridiculous since I didn't need glasses (I just turned 47), but when I put them on I was astonished at how much clearer the complications were. I didn't know if the bigger 42mm screen would help, but I soon started to hope it would. When I eventually switched to the 42mm I was amazed at how much clearer the complications were to me, in fact the whole screen seemed to pop more with the extra space. - The touch accuracy on the 38mm screen is more precise. I kept finding that my touches were not registered all the time and I suspect it was because I hadn't hit the sweet spot. Even after a few hours with the 42mm it is much more forgiving. Even simple tasks like entering the passcode are significantly easier on the 42mm vs the 38mm, and there is currently a lot of dismissing that you have to do that I hope Apple will reduce in future upgrades. When I got the 42mm today my first thought was that it looked huge compared to what I was used to from the past few days, but the improvements in visuals and touch I described above made me think that I would need to live with the 'bigness' for the sake of practicality. However, when I asked the two people whose opinion I value the most, my wife and daughter, they both said the size looked great on me, so I guess the deal is sealed, the 38mm goes back. So the bottom line here is that how it looks is not the only thing to consider. The size of the visuals is critical and the practicality of fat fingers on a small screen may really annoy some people over time. I not saying that you should choose one over the other, but you have to spend some time with both, and more than a few minutes at the Apple Store with the demo rolling, its simply not the same. There are a number of trade offs to consider. Now to a couple of tips or insights: - There hasn't been much about this but I obviously had to switch out the watches on my iPhone, so I wanted to talk a little about that. Its easy to do, you simply unpair the first watch which causes the setup to be backed up, then you pair with the new watch and it will ask if you want to set it up as new or from a backup. The fact that the watches were two different sizes didn't matter, and the only thing I can see that didn't get restored on the new watch was the Apple Pay cards. So it's good to know that any time you spend setting up your watch is not lost when you have to switch. Having said that I hit a couple of snags. First, although I unpaired the first watch I didn't turn it off. When I paired the new watch the old one seemed to try and pair as well. I figured that this could only end badly (potentially in one or more bricked watches) so I cancelled the set up and turned off the first watch before I paired the second. This seemed to work fine, but for some reason when my wife called my iPhone it didn't ring at all. I also set up a series of shopping list reminders using Siri only to find they didn't make it to the iPhone when I went to pull them up. I rebooted the iPhone and I think that these issues have been resolved, even the reminders suddenly appeared. Don't know if this was related to the fact that both watches tried to pair, or simply because I restored the other watch's backup, but it was something to note. If issues continue I'll post another comment. - When I first got the 38mm watch I noticed that the astronomy and solar watch faces showed the right time but appeared to think I was in California. On the astronomy face there was no dot to show my location, but the world seemed centered on California rather than the east coast where I was. Another poster had noticed the same thing but it had 'cleared up' on its own he said. Mine also resolved itself eventually and now the faces work fine. I believe the trick was that I had not been connected to a Wifi network at all when I setup the watch as we were out of town. As soon as I returned home and connected to wifi the problem was resolved. Just in case anyone else has this issue. - Initially I couldn't send my location in messages app. Another forum member helped me with this one as you have to make sure that the location service for the messages app is set to always on your iPhone otherwise this won't work. The error message I got wasn't helpful, but the other poster was, so I thought I'd re-share this one. - I got frustrated with the workout app and playing music. I walk for exercise and like to listen to music as well. When in the workout mode the glances don't work so you cannot swipe up to access the music glance to see what is playing or advance the song. MR posted hints today that solved this. You need to use the fast switching function by setting up the workout app as the first app and the music app as the switch out app, then you can double click the digital crown to easily shift between the two when you are on the move. Overall I love the watch, but to get there you have to first want to have a watch and fitness device in one package. These are the core functions in my opinion and if you can't justify most of the cost based on these then you'll probably be disappointed. Contrary to expectations the watch is incapable of raising your first born for you. It is limited in its usefulness and for those that haven't worn a watch in a while like me it is actually uncomfortable to look at it or interact with it for too long. If you have become frustrated with the constant noise your iPhone makes, and your inability to tell whether it is your phone or someone else's that has just dinged, ringed, or whatever then you'll love the ability to turn off all the sounds on the iPhone and the watch and enjoy being tapped when its something you need to care about. Siri works well in my opinion. I'm not a heavy user on the phone, but it is more useful on the watch because it can be activated with the 'Hey Siri' phrase. You need to limit the number of apps and notifications that you set up otherwise it just gets annoying. I'm a developer and I resisted even thinking about enhancing my app for the watch until I had some practical experience. Many developers are going to get this wrong before they get it right, but to the developers out there let me say that unless you are a user's primary app your glance is likely to get deleted as you only want ones that are critical in the list. Like the iPhone, the watch presents new opportunities. When the iPhone first came out many developers simply made their web functionality work on the iPhone, that was ok, but there was so much more potential as we have seen. It will be the same with the watch, developers shouldn't just take their iPhone app and push some functionality onto the watch, they need to use the new capabilities such as the haptics in ways that you cannot do on the iPhone because it is not as present and personal as the watch is. I'm just avoiding apps right now until some better ones come out as I just know that too many apps will kill an already sensitive watch OS and cause the watch to stop doing the basics really well. A long post I know, but hopefully there is something useful for some folks in here.