I'm conflicted about them. On the one hand, they're cheap and readily available and lower the barrier of entry into the sport, and they're reportedly pretty decent in terms of quality for being mass produced knockoffs from China. On the other hand, they're mass produced knockoffs from China - they steal IP from established companies, they put out the occasional lemon*, and they do some shady shit like using images of professional archers without license. Jake Kaminski had a whole thing with them using stills from his videos in their marketing material, and given that he's one of the best sources of free knowledge in video format it does rub me the wrong way.
*As far as quality goes, I haven't had any issues with their bows or accessories. I have friends who shoot their compounds, and one who uses their wood laminate ILF riser and likes it well enough with the exception of the tiller bolt set screws and limb adjustment screws working loose sometimes. The only Sanlida products I've used are their arrows, 24 for $80 and they're pretty much junk, I'm down to like 13 of them in less than four months. Some from hitting target frames (2x2 lumber, never had an arrow break from hitting softwood off a low poundage recurve before), and two that had fibers peel up after being shot into a bag target. The majority went in the trash during refletching though, fibers would start peeling up when stripping vanes or glue residue. Wound up relegating these to let friends dicker around with when they want to come over to learn to shoot, and got some Cross X shafts from Lancaster instead.