TL:DR Smart guides aren't accurate - even though the snap, (end up causing more problems in the long run) is there a way to fix it?
Maybe there are some settings that I'm missing (need to be changed)
I use my smart guides all the time (and am overall pleased with them). I do have my issues with it, as explained here:
A lot of times, when I'm trying to make a bunch of triangles like this:
Done by making a triangle, cloning, flipping, rotating etc. Repeat until full
(Perfect) Snapping using Smart Guides
Now I personally (with a strong attention to detail) will notice that there is something off after making just 1 or 2 triangles (Even before outline mode... strokes look oh so slightly thicker/off)
And then I check in outline mode... and sure enough:
Notice the line spaces (and this is in outline mode, so if I didn't notice it before, now it's sitting right in front of my nose)
The way I (seemingly) "fixed" the first image was by adding in a thick stroke outline so that masks out the difference, however, in a lot of my cases I don't want to have a stroke at all (and then you really notice the problems).