I had one. It lived 3 years never grew much stopes growing at around 3.5". They are sensitive and often become deformed with age. Some people have been lucky and grew out some really amazing fish that turn out to be short lived.
I had one and would never buy one again. Not worth it.
i also had a tiny EBJD that grew very fast to about 3-4 inches then didnt seem to get any bigger.... i sold it to a friend and ive not seen it for a while so no idea how big it is these days..
they do have a reputation for having a short life. if you search the forum you will find a member that had a stunner that made it to about 7-8 inches if i remember right. a magnificent looking fish but just died with no obvious cause.
i agree with snowflake and would stay clear of them and get the normal JD if this is what your after. much cheaper too