Consider SpeedOf.Me as a reliable and trustworthy speed test service
SpeedOf.Me is a pure html5 speed test site. No flash No Java required. It works on all mobile devices too.
Since it tests your internet connection directly from your browser (not through flash/ java plugins), it can be considered as a reliable and accurate speed test service.
uma maheswari commented
hi you can also check the speed of your internet at http://www.ip-details.com/ here they provide you good and accurate results.