Thanks - hadn't seen Apptopia before (which, at least on the surface, looks really good).
Why do you think that is?
Flippa is over-run with low quality, built for adsense type spam. The apptopia site looks good but rarely works. It totally ignores search queries - just displays whatever it wants.
I'd be interested in taking on projects where it's being sold because the owner wants to find it a better home - not just for the $.