yeah even playing with the preview and using the sliders it's super slow apart from that it's amazing! Do some work on the perf pls.
It feels like this is the sort of tool one needs (very) infrequently, and those cases don’t seem like the sort of thing where seconds really matter. I think it’s plenty good enough.
I prefer to focus on how grateful I am that the author has made this and published it for free.
When one first opens the site and nothing happens for 30 secs. you assume that the pdf you're looking at is the actual result (that happened to me, at least), then the other one pops up and you're like ... ooooh I get it!
Most users wouldn't be as patient and just leave.