generally a good rule of thumb, though ive also seen a few cases of a good open source app having a bunch of scummy forks that end up being more popular on the app store (eg shuttle vs phonograph). i wonder if google promotes apps with advertising more than their ad-free counterparts? the conflict of interest is so obvious but i digress..
Generally I trust the Fdroid repository much more than I trust Google's repository. Though if Fdroid became very popular with the masses I don't think that could continue to be the case, unfortunately. It's a difficult problem to weed out the bad apps...
