I am currently enrolled as a part-time student in St. John's University School of Law's LL.M. in Bankruptcy program. I am also practicing as an attorney doing corporate bankruptcy. In my opinion its a very good program for several reasons:
1) The professors are mostly comprised of U.S. Bankruptcy Court Judges and practicing attorneys. This provides you with an excellent opportunity to network and to get some outstanding letters of recommmendation for future employment.
2) The program is very comprehensive and provides you with a solid understanding of the bankruptcy process. Bankruptcy law can be confusing at times, but it certainly is not as broad as, say, tax. The classes have a decent amount of overlap, which really helps reinforce the core bankruptcy law principles that you learn.
3) Job placement has typically been very good at AmLaw 100 firms and clerkships for U.S. Bankruptcy Judges. However, I have heard that in the last couple of years, that with the state of the economy and the glut of attorneys that are looking for jobs, many firms are not hiring Bankruptcy LL.M. students at the rate they used to. Still, if you are interested in bankruptcy law, an LL.M. would only make you more marketable and you would definitely be far more familiar with the substantive law than many other candiates.
The real question that you must ask yourself is: Is $42,000 in further student debt and a year's worth of lost income worth it? Obviously, only you can answer that question, but the quality of St. John's Bankruptcy LL.M. is very good in my opinion and worth the time and money if you feel that you want to practice bankruptcy law.