Worth mentioning that Saucelabs takes security very seriously. If anything in this email is true (I can't speak to it at all), then I wouldn't use BrowserStack for testing anything connected to my systems. Sauce, on the otherhand, destroys every VM after each use, guaranteeing that you get a known good (and uncompromised) state for each usage. And unlimited manual testing is $10 a month, which is a great price.
(Disclaimer: Former Saucelabs employee. Currently doing other things unrelated and don't keep in touch, but I definitely know the Sauce claims in http://sauceio.com/index.php/2011/09/security-through-purity... are true.)