I couldn't tell you much about the BH. I know a guy who bought a BH several years ago (cheap end) and found 2 silver dollars just playing around with it.
However, there is much more that you need to think about before buying a detector.
#1 - what can you spend. As with most things you get what you pay for. The more you spend the greater the depth the more likely you will find something of value.
#2 - what are your physical limitations? Some machines are extremely light others are heavier.
#3 - what are you wanting to hunt? Coines, relics, beach hunting, etc. A wide range of options and a wide range of detectors to meet your desire. Some detectors are better suited for certain conditions.
#4 - do you want to learn how to detect? If so I would suggest staying away from detectors with IDs - they give you a suggestion of what is in the ground. A lot of people are going to balk at this but IDs are first not 100% accurate. Second, they can make you lazy in that you trust them and you end up not digging up things that you would want to dig up. Let me give you a comparision. Kind of like teaching children math - one group you teach them without using calculators and they have to show their work. The learn math eventually. A second group you teach them without showing their work and they get to use a calculator. In the end I would say after a long period of time those who learn math without the aid of a calculator will be better and score higher. Same with a metal detector - getting one without an ID will force you to learn the detector, its sounds, and you dig a lot more junk - yuk - but you also find those gold rings that show up as junk more often.
There are a lot of good detectors - if you learn how to use them.
Two I would look at -
Tesoro Silver Max. Very light weight, excellent depth for the price, and easy to learn and it has good discrimination if you choose to use it. Lifetime guarentee and priced in the $250 range I believe.
Another a bit more expensive but a great machine - Minelabe Advantage Musketeer. Heavier machine and a bit more complex but gives you more depth.
e-mail me and I can give you additional information or some direction to go. I'll point you to places you can find out information and discuss it with those who own the machines.
Mike