Doesn't seem too popular just yet but I think as more people check it out they'll gain some traction.
It will, as soon as this group of people starts thinking rather than just going with 'whatever is the biggest pool'.
One part knows what they are doing, another big part probably not, and a small part does not give a shit.
While I do advocate for pure PPS pools (biggest advantage to the miner), I do realize PPLNS is probably 'the' perfect system for new pools.
It needs no startup capital, it's protected against exploiting by hoppers, & it rewards miners fairly.
Give it a year and prop. pools will be history, PPLNS will be the most popular