It depends on what you're looking for. Sedo if you're looking for offers and get some ad revs while you're at it.
Forget about Sedo. They cheat big time! They always count the lowest paying click if anyone clicks more than once per visit. For example, you click two advs, the first and the last, on a parked page, Sedo gets 2 commissions, but it only shares the cheapest one with you. Let's say the first adv pays $1/click and the last pays $0.5/click (after Google's 50% cut). Sedo gets about $0.65 + $0.33 = $0.98, but you get only $0.17. That's why a lot of people complaint about their revenue drop very often. It's rare to see over 100% click rate.
Check out the link on my Signature. I got $10+/click! Actually none of the clicks on my domains went below $0.25/click and almost half of them are over $1/click.
You have to have at least 200 high profile domains or a portfolio earning over $200/month to get into SedoPro. Parked is easier to start with. I have a link to it in my signature below.
Thats correct and Parked will analyze your portfolio before letting you join. NameDrive doesn't have any kind of requirements, it's a good start.
I'm in the same boat. I have about 30 domain names that are parked with NameDrive and Parked. I have been buying the domains with the intention of reselling them at some point. In the meantime, I was hoping they would generate some income. Thus far they have been making pennies. Is it more profitable in the long run to develop them as sites? Would this bolster their resale value? Or is something like whypark a better option? Thanks in advance.