I've integrated Uppy into my project Jopro for image uploads. It's been great so far! The only thing I dislike is that a lot of the benefits come from using it with Transloadit (which makes sense since they developed it) which is a SaaS. For now there's no issue with having to pay too much but I imagine as users come it may be an issue. For now it works great and you do get a lot of things that are easy to use. For example I have uploads working from ~10 different social platforms and also an in app editor for cropping, rotating, etc. that really wasn't an issue to add. Integration with S3 was quite easy as well, though I need to modify the permission structure soon.