I’ve got a Nexus 5, and briefly activated Google Now when I first got it, but all it seemed to give me was a weather forecast, which I can get from the Beeb, so I switched it off.

Am I missing anything?

I use it loads but mostly because it tells me traffic conditions to and from work at commute times and time to home at all times. It also sends me notifications at commute time if the roads are slow for some reason. Other than that it’s weather, updates to websites that I use quite often (e.g. xkcd) and things like package dispatch updates.

It gets better with time, it will work out your regular haunts I.e work, and provide traffic updates, and will give updates on frequent searches such as stock prices, product news etc. Plus loads more like sport results, birthdays from calendar etc. I’ve got the full screen widget on one of the spare home screens, but not the default one.

Scarily accurate, but seems to kill my battery – I generally avoid it because of this.

You can put in ‘home’ and ‘work’ locations, teams that you support (pretty limited to football as far as I can see), stocks/shares that you own etc. and it will keep you up to date with those.
If you use GMail as your primary personal mail, then it will root around in your e-mails and dig out appointments etc. if you let it and remind you of things.

I keep trying it for a while and then giving up on it. It never shows me things that are of any interest to me and as mogrim says, it seemed to spank my battery quite badly.

Played with it for a while on the iPhone. It works better the more Google products you use (natch) so use Google Calendar for appointments, GMail for mail, Google Contacts, plenty of navigation with Google Maps and have your home and work locations set.

It was quite spookily accurate but it does seem to kill the battery (probably from hitting the GPS regularly).

Sports results/fixtures, traffic, meetings, time to airports etc. all useful stuff

It told me my Dad’s flight was delayed, and estimated arrival without prompting. My Dad had emailed me his flight details months before…

Kinda Big Brother-ish but useful on occasion, for example it tells me the estimated time home via bike and/or metrolink

Use it all the time. As above if you give it access to your info it feeds it back at the appropriate and most useful time.

Switching off the Google Hot Word improves my battery life.

I’ve been using it regularly, as I drive all over the country and it’s fantastic at sorting out better routing when there are traffic problems.

It was also spanking my battery on my note 2, but over the past week or so it seems to have calmed down and there isn’t much difference in battery usage compared to my works note which I haven’t activated Google now on.