Accurate tool for ranking

You really can't trust any of tools 100%, as the results vary depending on the IP/proxy you might be using. I find rank tracker serving my purpose, but it's very time consuming.

I use a combination of things:

Rank Tracker ( you can see your ranking last 10 years) just click the "progress" tab in the lower left.

I have Traffic Travis Pro (v4) and it produces pretty decent, straight forward graphs.
I also use Traffic Travis (free edition) for fast, on-demand ranking updates. V4 is a pain to force manual updates, you have to change how many results to check to get it to update more then once a day.

And I simply go into "private" browsing in chrome and search that way. If you don't do the private window big G saves your seraches and will show you your site based on your interests giving false rankings.

You can also use if you want, limited to 3 searches a day.

There are no accurate results since google has several data centers worldwide updating in a different time. Plus, each country (google.de, google.es, google.uk etc) sees different results

i use MS, but also double check with chrome incognito mode

Sescout is good as well as it auto updates.. Another thing i use is rankerizer.. So i could compare them and see my ranking trends..

I use AuthorityLabs web service. Very useful if you're managing several clients.