I am loving routines, but I also hope they push out an update to allow for more advanced routines and/or more options. I used to use a third party app for things like this but it had more options and was much more detailed in terms of setting up very specific parameters and exceptions. With that said, I like that this is simple, integrated, it doesn't seem to be draining my battery having several routines running, and lets you toggle notifications off (vs the always present notification of the app I'd used previously - hate that).
Reliability has been great so far. The least reliable part of my routines seems to be work, which is funny because I have better reception here than I do at the two other locations I have routines based on (plus, the radius is plenty large and includes the entire campus so to speak plus major roads nearby). Sometimes it works as expected, other times it takes a while then suddenly recognizes it should be running (I've been testing it/leaving things as-is to see if it ever kicks on). With my other routines, they seem to kick on as expected without hiccup.
With routines I have been able to keep off all of the schedule things like blue light filter, do not disturb, night mode, and most importantly the WiFi settings that help identify when you're home to kick on (I almost never use public WiFi). I heard that last one impacts battery, and I was glad to not worry about it. I like that routines gives more flexibility vs those schedules anyway. For example, sunrise/sunset is the worst setting ever in Alaska. Plus, those schedules let you select days but don't let you differ the schedule for different days. With routines I don't have my phone sound back on at 0500 on Saturday morning like I do on a workday.
Routine based unlock has also proven more reliable than Smart Lock for me, which I appreciate.