[wackget]

There's something disagreeable about charging a subscription to search freely-available scientific papers.

Yeah I get you're technically paying for the "advanced" search but it still leaves a bad taste in the mouth because this service's entire existence depends on open source knowledge.

P.S. hiding pricing behind registration isn't cool

[bbsz]

I think that full text search queries over long text data is already kind of expensive server side. Users are paying specifically for this, not better UI or simple direct match search available in free to use projects. I would say it's very reasonable to charge for costs incurred here.