Recording breaking performance numbers were recently published for SQL Server 2014 for various hardware systems.
TPC-E (which measures the online transaction processing workload) and TPC-H (which is a decision support benchmark) numbers at the link below show SQL Server in the top ten price/performance for different hardware and OS platforms.
TPC-E: http://www.tpc.org/tpce/results/tpce_price_perf_results.asp
TPC-H: http://www.tpc.org/tpch/results/tpch_price_perf_results.asp