Digg reader randomly losses state and shows me days of stuff as unread again. I also frequently have to use "mark all read" to clear out the bolded feed name, even if there are no items shown. I've also seen it stop updating a feed for days and then suddenly showing a half dozen items.

I use Digg reader because it seems better than most alternatives, but it's not as reliable and consistent as Google Reader.

I don't think Digg Reader does search. Digg is good though, it's what I use.