hi mike,
GSO is the manufacturer of the dob, bintel relabel it and sell it (they are a shop). I am assuming that the other shop you got your price from is andrews communications?
there are differing oppinions on these shops. bintel for aftersales service and a great range of equipment, andrews for price... it comes down to what you prefer and what experience you have.
keep asking questions tho so we know where you are coming from