L620 here.
My story: after hard reset glance was there and I was able to set it up, it only showed clock thou. Then after updating apps via store beta the glance option from menu is gone (it was in extras), but the glance screen still works.
The battery life is bad for me, I wonder if its related to glance or not, even with battery saver ON it drains ~ 6% per hour. If its related to glance I am happy to turn it off (thou I'd have to do another hard reset) as I use it on my daily driver (not a heavy user so can afford a couple of bugs).