I like that series, as the author does not try "bash" the competitors or excessively promote Ardor's features, but describes also the advantages of the competitors in a fair way. The series is confirming my opinions, until now, about Lisk and NEM, but I got some extra insights difficult to obtain from the official pages of these projects. I see Lisk as a more direct competitor for Ardor because of the sidechains feature, while NEM is more of a competitor of NXT, Peercoin, Waves and other more traditional PoS blockchains.
(In the NEM article, one paragraph - that one beginning with "Perhaps the most fundamental one ..." - is tripled, please correct. Thanks!)
That would be huge for ARDOR if they can beat LISK to it.