I'm big on (i.e. extremely picky on everything to do with) color, so this is my take on the prints!
#1: Cheerful and whimsical. The dogs aren't visible as dogs from a distance, but the curving lines of the outlining does. And it looks like an interesting, non-traditional pattern, with color involved. The white/blush/black proportions seem balanced and don't go muddy.
#2: Lack of actual color; it's all neutrals. Also, small dots (any small scale pattern) tends to either disappear from a distance, if widely spaced, or just muddy the effect if they're closer together like these are. Style may definitely play into this; it looks heavier. I might like this if it were (a) drapey and (b) on a pastel color background. Or with bigger dots. (Though personally I don't do all neutrals!)
#3: Love this! Big pattern, lots of color and difference in contrast levels, but it has movement, too. I want this shirt for myself!
These are extremely smart questions to ask! It's taken me a long time to learn to analyze items that I should like but somehow don't. Though when I do, it's incredibly helpful, and keeps me from a lot of unsuccessful p7ruchases.