If your budget can allow for the very slight difference in price between the 5000 and the 6000 you definitely make up for the additional cost in features.
The 5000 and 9884 are essentially the same deck. I like Alpine's SQ better, but the 5000 has 3V (maybe 4V) pre outs. The ipod control on the 5000 has an extra line of display (All it does is tell you what menu you are in: