I find having google now on effectively the left most home screen kind of more handy.

not especially so on my tablet really but definitely on my phone. i'm more inclined to use it. i take a glance whenever i have my phone out of my pocket.

I have put it on my Nexus 4 and Nexus 7.

I have found it a little sluggish on the '7', but I think that's because mine is getting sluggish in general. It does work quite well. It took a while to get it working with Google Music and it isn't perfect, but it is great for playing tracks in the car!

It is definitely better looking. I was never a big fan of android's black bar. I've installed it on my old rooted phone and that seems to pick up my "ok Google" a lot better for some reason. My phone is older, maybe it just has a better mic, who knows?

when I tried google now, all it kept saying was the weather and told me what time to leave home for work and that it would take me 25 minutes to walk there and when I was at work, it would tell me it would take 25 minutes to walk home

I knew that anyway, I don't need a phone to tell me. I know i tried it out for a few days before I disabled it, but if that is all it going to tell me, then a waste of time having it on.

it tells you a lot more, but you need to have it on for it to start learning what you do.
mine has started pulling content from various sites about topics i have recently viewed or searched.

you can add sports teams to the list of data as well.

google now won't do anything else for you because you're paranoid about telling Google anything about yourself. It needs that data to do cool stuff.

I had it on for two weeks, but it came up with the same thing time and time again. not into sport much to be honest.
what should i tell it?

you don't have to tell it anything.
it just learns what you do over a period of time.
if after two weeks it's only giving you weather and travel home then it sounds like you don't do a lot on your phone.

Obviously if you walk to work then the journey time is going to be the same every day. That feature is more for people like me, whose driving journey to work is around 30 minutes and involves the sometimes accident-happy J18 to J15 stretch of the M1. Whenever there's a snarl up I get notified it in advance, and to me that is worth its weight in gold.

Similarly, I'm guessing you don't use Google Calendar because why on earth would you want Google to know what you're doing and where you're going to be?! However, for those of us that do, the "Time to Leave for..." facility of Google Now is absolutely bloody brilliant.

another thing google now does is tell me when there are updates to sites that i read.

I've removed GEL from my 2012 nexus 7.

it made it really really slow. jerky.