I wish it was limited to just rectangles but I'm talking about literally every element snapping could apply to, and I'm not talking about the pixel grid (which isn't perfect, either) I'm talking about guides, anchors, edges, etc. While zoomed out, you can snap something to something else and the UI feedback says you are snapping to that element but when you zoom in, it's totally not where it's supposed to be-- like, hardly ever... at least 75% of the time.
I guess precision is just not important to the Illustrator community at all, judging from the lack of replies and/or views on this topic, and the fact this has been the way Illustrator is for the last few versions, at least back to CS2.