I got a breeding pair in my 450 g tank.
MB are very hardy. You will almost never see a sick MB, just thin ones. There are many report that MB is the only fish survide a tank wipe out. It maybe dificult to get them to start eating as they initially only eat live food. Have the LFS feedthem and see if they eat frozen food for you.
If you have a large tank with lots of live rock, your MB will be fine. I had my older MB for 5 years befor i see him eat Mysis shrimps They other MB, I have had for about 2 years.
Don't expect to see your MB very much for the first years or two. After that, they are often out. My MB eat frozen food very well these day. They can gorge themself with frozen Mysis like the rest of the fish in my tank.
All in all, they are excelent reef fish (they may like fancy. expensive shrimp dinner, especially righ after the shrimp molts) BTW, I have not loose any shrimps in my tank due to the BM yet. May be due to the shrimps were in there first, and it is a very large tank.
Let me know if you have any specific question.
Also, there were two articles about MB in Advaced Aquarist. and one article in Reefkeepers last year. Here are the links
http://www.advancedaquarist.com/issu...t2002/Fish.htm
http://reefkeeping.com/issues/2002-04/hcs3/index.htm

Minh Nguyen