The author cited has vastly expanded the list at the original link above and there are some interesting search engines with their own indexes. So it's worth re-reviewing that article. It shows that the field is expanding which is a good sign.
A couple of initial thoughts:
Right Dao - I find this search engine to be mysterious and evasive. They keep their cards close to their chest. Results are surprisingly good for the size of their index. Checking over at WmW, nobody has ever seen a Right Dao crawler so it must be pretending to be something else. There is information about this engine missing from the puzzle.
I do get a lot of errors when I try to use it.
Gigablast - For years Gigablast seemed to be stagnant, dormant, the index at 1 billion and feeling stale and I never liked the algo. But they must have come into money because the index is fresher, seems way bigger, and the algo very much better.
The rest like Alexandra and Yep are also interesting.
Mojeek is way ahead of all these in relevancy, size of index and privacy. But the pack is forming behind it.
