I like the drop system at bosses, thats the main reason why im on Epona.
If youre lucky like some of my clannies, then you can easily get rich.
Another reason is that many people are friendly, funny and ready to help.
The drop system is also probably what I like best about Epona but it's a double edged sword partially because of your second reason. Since only higher level bosses are class roll it happens where higher level players will have say a mind tablet of marble drop on them and then they "get" to keep it and sell it probably for around 20k gold more or less possibly to the same mage who was there when it dropped. However you can be grouped by anybody if your at a boss so you don't have to worry about another clan showing up and you having no chance at a drop at all. I is harder to get into a clan in the first place thought and without one it is very hard to time your own bosses as unless you camp hard core or get lucky you will never know when most bosses are up. I know "getting rich" is more referring to engame loot but lower bosses spawn more often and as a higher level it's easy to get some valuable drops and sell them by taking them away and then selling them to those who needed it in the first place.