I used interviewing.io and pramp really heavily in my most recent job search. I found that interviewing.io interviews were of a much higher quality in general vs pramp which was pretty hit and miss, some interviewers were well prepared and helpful and some clearly checked out after their half of the interview. But I ended up using pramp a lot more since they had unlimited interviews and used interviewing.io as benchmarks to see how close I was to where I wanted to be. Recommend them both!