Google analytics is the tool wherein you can track the working, the ups and down of the keyword position so i think this the best option to track the Keyword position of the site
I only check Google position of my website manually because almost all tools show result 100 top positions.
IMHO there is no tool which can give you 100% accurate results as far as Google SERP positioning is concerned, so my suggestion would be to go for a manual check.
Google usually filters those users or software the are getting results too fast or full of ads, making their services not so reliable and inaccurate.
Try Rank Checher - it's a plugin for Firefox, you can type in as many KWs as you wish and also the domain you want to track. It's great.
Well... In this case the Google analytics ... I am using this tool to check the page rank and its update position...
lots of tools are available on internet, Rank tracker is best one according to me if you have registered version of rank tracker then you can see position changes in search engine, so it will helps you to track position of your keyword.
I use the "Google position checker tool". Just run a search and you will find multiple services coming up for that.
Accordign to me there are many tools but no one can give you perfect results. So I think you have to do manual check.
You can use SEOSerp Checker, but sometimes the site is down so you can also use SEOCentro. They have different output but not far from each results. And it is also better to check keyword position manually.
sescout.com it's a good service with good historical charts. Although it's paid, can test with some keywords for free.