I moved my domains to Parked from Sedo around Nov. 1 of this year. The first month was great and I probably saw a 50% increase from Parked over Sedo.
The last few weeks at Parked have been absolutely terrible and the domains are "dead in the water". I may end up owing Parked money at this rate.
At least at Sedo, I received acceptable offers from time to time and had a few that sold for nice prices through their auctions. I have a brother and brother-in-law that I'm going to teach some of the basics of domaining to. I had planned to recommend Parked to them, but unless things change soon, I can't do it.
In defense of Parked, I do really like the user-friendly interface and ability to select photos, etc. Maybe I'm missing something, but I don't understand why parking companies can't make landers that look like "real" sites (although I did see a great one from SmartName recently). Just my 2 cents.
REdomainer