Microsoft and Prometric have renewed their Second Shot promotion for certification exams. This allows you to retake a failed exam a second time for free, (which is pretty good insurance since the regular exam fee is $125.00). You can get the details here.
You might not know that failed exam attempts do not show up on your Microsoft Transcript, so there is really no reason not to schedule and take an exam with this promotion. I firmly believe that getting getting certified is a good thing to do. It shows that you have taken the initiative to further your career, and it can help you get further through the screening process if you find yourself in the job market.
Glenn Berry's SQL Server Performance 