I also prefer DD but if I can get one splined end in there it really helps if you need to change the "clock" of the steering wheel a few degrees. With the DD you can only change the clock position 180 degrees at a time.
Both are extremely reliable and if you happen to need to change the clock position a few degrees you're going to wish that you had used at least one splined joint. The DD has really gone down in price on ebay!!
