Do you have to have the specific number? The activity rings are a really good visual representation - much better than how it's done on my Garmin IMO.
I agree with this. The activity rings are a nice visual indicator of how energetic or how sedentary you have been for the day. There are many days when walking about 5 miles (mostly to and from work) is the only sustained activity I get. The Exercise ring is an indicator of how much of my walking was vigorous enough to get my heart rate up. I can tap the Activity complication to see details, and then swipe up to see the number of steps taken and distance traveled. I wore my Apple Watch with my Fitbit One for 3 months and the steps were always really close, but your mileage may vary.
How useful is the Stand ring? Well... it's useful to me, but maybe not as much so as the other rings. The harmful effects of long-term sitting, even for people who are otherwise quite active, have been getting more attention in recent years. I have a job that requires a lot of sitting. Even though I was getting a lot of exercise walking and bicycling, I started to have all kinds of sciatica problems as well as other leg and back pain. Long before I got the Apple Watch I started using iPhone reminders to get up every hour and walk a short distance before sitting back down. I feel like it made a big difference and my issues went away (don't know if the long stretches of sitting were the cause or not... just saying it felt good to get up and stretch...so maybe there is something to it).
I usually have the Activity Rings set as a complication to remind me throughout the day that I need to get up every hour, go for walks when I can, take the stairs, etc. Even if I log plenty of exercise and steps before I even get to work in the morning, it's still good to have the reminder to get up and move around so the rest of my day doesn't undo the exercise I got in the morning.
Of course there is a nice simplicity in setting a step goal and watching your step count, especially since you know exactly what to do to reach it. I check my steps frequently... maybe it's because that was the primary indicator when I wore a Fitbit, so it helps me compare the last seven months to the previous year and a half I was a Fitbit owner. As others have mentioned you can get third party app with a steps complication that you can display on a watch face, but I don't know how well any of those work. I'm sure there are some threads about this.
The Apple Watch is not the top of the pile as a Fitness Tracker, but it works fine for my very basic needs in this area. If you want the Apple Watch for all of the other smartwatch features that it excels at, you might find you are willing to compromise on some things. I think it will improve over time as a fitness tracker, and if you are on the fence you might want to consider waiting to see what (if any) advances March will bring.
Sean
