Stoller interview questions

Applied online and received an email requesting an interview. Had a phone interview which went pretty well. The work was similar to work I've done before. A few weeks later, I was requested to come for an on-site interview where I spent approximately 4 hours of my workday speaking with 3 employees with whom I would be working closely followed by an HR manager. The conversations went smoothly and I felt really positive about my chances. I sent thank you emails to each person I met with. Weeks went by and I did not hear any word so I contacted HR and was told they went with someone else. I asked for feedback but received none. That left a bad taste in my mouth. Would not apply with them again.