I've gone down the sugar daddy path and like any relationship it has its ups and downs. As to whether or not they end up in "disasters" as Dood put it, this depends on two things.
One is expectations. If someone's expectations either change or isn't met somewhere along the line one of the parties will get hurt.
Secondly, if you can't pay the price, you're definately going to get hurt. The price isn't money, it's that if you have an SO and they find out about this relationship, there's going to be fall out. One always hopes it will never happen, but be prepared if it does.
As for the money aspect of it, I have two schools of thought. I've loaned my SB money I never got back. The second time she asked me for a loan, which was about a year and a half from the first one, I said sure, but since I know you can't pay it back, consider it a gift. She never really meant to stiff me and it wasn't huge $$, but the fact is she's a single mom, and has ongoing money problems, otherwise she wouldn't be in this type of relationship, and we often go months without seeing each other. So she pays off some bills and more come in..that's life. My view is she's a bit like a daughter in the sense of me helping her out, and bit like a lover when we meet. I view myself as a part-time boyfriend, older brother or perhaps a dad, so helping her out isn't just about sex for your dollar, it's about helping someone out who needs it, is worthy of it, and you don't mind doing it. In fact on some ocassions I enjoy it.
But in general the money aspect is pretty simple. One simply needs to ask themselves, what is the price you're willing to pay for these kind of memories?
The flip-side is she's pretty much always been there for me, and both a friend and a provider and I've seen her countless times over the years and she's drop dead gorgeous. To me, there's something special about having sex with someone who is both gorgeous and you care deeply about. It's more of a complete experience, than a conventional SP relationship, but that's just my opinion.
When I look back on it, I'm more than happy with the arrangement, and to the best of my knowledge she feels the same way.