I have been through a number of watch faces that have options for metrics (I like a lot of metrics on my watchface) and they're usually a drain on the battery (expected) rails, might be the best I've found. There's a bevy of options for face metrics and themes, but the watchface also isn't the big of a battery hog.
It also has a baked-in night time battery saver mode where all the metrics are removed (and polled) on the watchface. This is brilliant since I'm not looking at any of those things at rest.
I had to charge my 945 last night and put it back on right before I went to sleep. With Rails my battery drain during sleep was 2% for approx 8 hours of sleep. Every other CIQ watchface I've been through has bordered on 10% use at during sleep.
It's not super flashy, but Rails is really good at keeping the battery drain to a minimum on this watch.