Celebrex continues to sell, while Vioxx got yanked. Courts, doctors, patients, and investors will decide which approach is better. Big Pharma rivals Merck (MRK ) and Pfizer (PFE ) have reacted differently to the safety issues swirling around their respective arthritis pain drugs, Vioxx and Celebrex. How the drug giants have handled their high-profile problems offers a glimpse into each outfit’s culture and management team, and their differing approaches also may provide investors with clues about which is best positioned to handle the fallout in the long term.