I am missing the option to see the remaining battery life as time in the menubar?

You just can't show the remaining battery time in the menubar since Mountain Lion.

The following free app uses almost the same icon design and adds a bit more features which makes it a valid replacement:

Battery Time Remaining

by Han Lin Yap

You can read my blog post for some more detail on what I did, it also won't hurt to report a bug to Apple. So this issue will get to their attention.

According to the following blog entry Apple removed the option deliberately and it won't come back:

http://www.macpoint.be/mountain-lion-is-coming/

I also missed the option, so I wrote an App. It's in beta now:

http://batterytimeapp.com/

SlimBatteryMonitor

Not only does it save much more space in your menu bar, it lets you choose what information to show in specific states.

I have mine set to show the time when running on battery, the percentage when charging, and just the icon when fully charged.

A cheaper and simpler option than the still-awesome iStat Menus is Watts for USD $6.95. Very configurable and lets you schedule reminders including re-calibration.

I've been using it on 10.6.8 on my last three portables and am very happy with it.

I made a very simple app to specifically show time remaining: Battery Time Remaining