Perez is less qualified than Palin
Perez has run a federal department and is familiar with national issues due to his posts in the Justice Department and Labor Department.
Qualifications aren't just a matter of how long someone has held statewide office.
Palin had spent two years as Governor of one of the least populated states. Governors are also vulnerable to being unaware of events outside their states, especially relevant for an Alaskan, given the state's geographic isolation from the rest of the country.