I'm sure I'm going to be saying what everyone already knows, but...
After buying an official dakimakura for a pretty penny, I got to wondering if bootleg dakimakuras were all that bad, and if it would be better to spend like $50 on a bootleg over $100+ on an official one. So after asking for the best bootleg site here and getting moemarket as I response, I tried them out. Before I get to the autistic analysis, I should note it took a month after order to get the goods delivered, though Christmas season might have something to do with this. It came in a blank dark bag with only the shipping label on it, which had "Pillow case" on it but nothing else.
I got two bootlegs: a $50 one with the meme peach skin and a $70 one with 2-way tricot, the most expensive available. Both an extra $10 to be 50x160 instead of 50x150.
For texture, the peach skin was just terrible compared to the official. Never, ever buy anything with peach skin. The extra $20 for better texture is worth it. (Not sure how much other sites cost). Luckily I foresaw this and used the daki I least wanted as the peach skin experiment.
2-way tricot is better. I'm not sure what official dakis use, but they feel roughly equivalent. Maybe a slight edge to the official one I have, but that could be placebo. I would recommend getting this if possible, though the slightly cheaper velvet might be just as good.
As for art, well, ouch. I got two with somewhat old designs (2012~), which may have contributed to this, but ouch. It's pretty clear the images were blown up or modified in some way, presumably expanding preview pics somehow. There's no like, water marks on it, but the art feels noticeably blown up in places. The most immediate example is that sweat drops, which should be like... slightly transparent, are just solid brown. It looks pretty bad, like they're studded with tiny brown streaks. Eyelashes, too, look more stuck together than they should, and overall the image quality just feels a little worse.