Had some domains parked at SEDO for MANY years. More than 30, for more than 5 years. Other work became a priority.
Three things happened that made me lose any trust in SEDO.
1. Moving my site from a "Normal" Site to a SEDO parked page made my site disappear almost immediately from search results on google, etc. It was normally found on the first page of google and yahoo searches, but it disappeared quickly when I parked it. That sucked.
2. I found, from time to time, when I actually went to my site's link, at time's I'd be redirected to ANOTHER SITE. Nothing mentioned about MY Domain name at all. I remember contacting SEDO and they said something to the effect that they were "testing" some things. I feel it was a basic hijacking of my sites.
3. Over the 5 or so years I had all my domains parked there, their statistics showed little to no hits or activity. In total, I have in my SEDO account around $13.00. I have a feeling they profited far better than I did. But, there's no way to know....
I am just getting back to them now, and am FINALLY moving away from SEDO. I am going to put most up for sale over at Flippa and see how I do.
If I decide to park them again, it definitely won't be with SEDO. Probably put the effort into doing sites and adding adsense.