Having done it myself, I can assure you that it's not worth it.
Hundreds of hours of backend work designing and setting up the server, and hundreds more improving it once the server was released in the time since last summer has yielded a steady playerbase of 0-12, usually 0. We advertise on 10 different voting sites, have custom-made plugins (server runs 65+ plugins total), a custom resource pack, custom terrain, and all of the other classic features that players look for which all combine to create a genuinely unique MC experience.
I even pay for 12 gigs of RAM.
All of that being said, not that many people ever join, and those that do rarely stay. As is to be expected, there are 5-10 veteran players that play pretty regularly, but generally they are the only ones on.
It can be very rewarding to run a server, but it takes a ridiculous amount of resources (connections and cash) to keep up a medium sized playerbase today.
