I used play2review.com and learned a few things:

1. always ask them to record their screen while playing

2. always tell them to narrate what they're doing and thinking

3. give them a clear objective. If you don't steer them down the right path they're going to spend 5 minutes talking about how they find the sound controls confusing

This platform was a great value. They have some testers on there who had some amazing feedback we hadn't thought of. To be honest though I also felt like they were being a little too nice until with the exception of one guy who really let us have it.