A major investor advisory firm has recommended against shareholder approval of T-Mobile USA's pending merger with MetroPCS. According to Bloomberg, Institutional Shareholder Services Inc. told MetroPCS shareholders to vote against the deal next month. In a report to investors, ISS says it's opposed to the deal because it feels that MetroPCS could do better on its own, even though MetroPCS would need to acquire more spectrum to stay competitive. "The question remains, 'Why now?'" ISS said in its report.