SolPad Software Engineer interview questions

Was contacted by a recruiter and offered an interview over Skype. Asked to substitute Skype with in-person, the panel agreed. Had 2 on-site interviews, one 1-hour long and another 4 hours long, both times with same people. The questions were all over the board from low-level hardware operation to C/C++ to network design. Answered all, better than they expected. No offer, no explanation. My guess is -- some of their team members were predisposed not to hire me. They probably had their way over "the good guys". On a second thought, their reported salaries on Glassdoor are below my range, so no worries.