PingPong is described as 'Effortless remote user research. You know that talking to your users is essential, but until now it has been painfully complex. PingPong takes care of all the hard stuff and saves you days of work. So you can be interviewing users in minutes!'. There are more than 10 alternatives to PingPong, not only websites but also apps for a variety of platforms, including Mac, Windows, iPhone and SaaS. The best alternative is Teston. It's not free, so if you're looking for a free alternative, you could try UXtweak or Poll the People. Other great sites and apps similar to PingPong are UserTesting.com (Paid), Userbrain (Paid), UserBob (Paid) and userinput.io (Paid).
Test an unlimited number of websites, ask an unlimited number of tasks or questions and invite 1000 users. Loop11 is the best available tool if you are wanting both qualitative and quantitative data from your test participants.
UserFeedback provides written feedback about your website from real people. No changes to your website code, no complicated test setup, no recruitment of testers. Yet, high-quality feedback in under 24 hours from people in your target audience.
Userfeel.com provides remote usability testing using a multilingual panel of testers speaking 40 languages. Additional features: Automatic video transcription, tasks timing, SUS calculation (System Usability Scale), highlight reels creation and more.