DRW Desktop Systems Engineer interview questions

Challenging, intimidating, lengthy. 7 rounds total, including an almost 4 hour onsite. Was told after the final round they loved me but had one other candidate they wanted to interview first and then would decide between us. After that candidate had their final interview they told the recruiter they would be passing on both of us and starting the search over with no feedback. The entire process took almost 3 months to complete and required me to take a 1/2 day of PTO. Some feedback on what I could have worked on would have been nice.