Haha, looks like they could put some of the article's suggestions to good use there. Home page of blitz.io throws a 500 Internal Server Error right now...
I had a weekend hack project like blitz/loadimpact, was thinking of charging by the test (ie you pay what you use, which makes more sense than charging per calendar time).
Plan was to offer quick tests (ala loadimpact), whole-site test (you give it the url to start, and it'd hit the linked pages with some probability as well) and custom scenarios (a list of urls to hit in order, rinse, repeat), and API to trigger tests automatically (for integration in routine integration/regression testing).
Got the backend working, never finished the frontend/UI. If anyone reading this is interested, let me know in reply - might put up a quick working demo page for it.
The free version can give you an idea of how your server will handle a small spike, and the other versions are per day so if you only need to test once or so a week as you finish a sprint then it wouldn't be a horrible cost.
It's odd that they let you just test any website without proving its yours (by e.g. putting special file in the root or something). Can't unauthorized testing be considered a DoS attack?
I can only speak for http://blitz.io. We generate an account-specific UUID which becomes a URL that you need to make available on your app (adding a route in ruby/node.js or uploading a txt file). Before each load test we check that your UUID is available on the app. Even if your UUID is leaked, this is not a problem, since it's unique to your account. Unless of course, your Google/Facebook account gets compromised. We currently, do not support password logins. It's either OAuth/FB Connect or SSO through our partners.
