SugarDaddyForMe.com is currently the largest sugar daddy dating site.
The user experience on the site is good overall. There are some pages that are a little sub-par in terms of visual appeal, but you're not dating the website. It's the members you care about, and Sugar Daddy For Me has its share of knock-outs. Of course, being the largest, you'll find some chaff in the wheat, but generally speaking there's something here for everyone.
We liked the many search options -- you can search by income range, body type, height and marital status, in addition to the more typical age and location filtering. There are some novel features like iPhone access and MySpace-like profile customization.
Pricing is in the typical range for dating sites. Be aware that the service is automatically billed monthly, so it's your responsibility to discontinue membership once you've found the sugar daddy relationship of your dreams. ;)
In the end it comes down finding that one person you hope to meet. Given the sheer number of sugar daddies and sugar babies here, SugarDaddyForMe is a good place to start. CHECK IT OUT