I use it extensively at home and many workplaces.
Server changed considerably in 10.7 -- GUI completely overhauled, tho it's much the same under the hood -- and IMHO was not mature until Mavericks.
The WGM is gone now with OD/users/groups shifted over to the Server app and granular user/computer management has now been shuffled off to the (garbage compared to a real MDM solution) Profile Manager.
For anything that doesn't require OD and MDM, the Server app is actually pretty nice to use at this point. (And now that it's reached this point, I expect Apple to kill it.)