Oh, I vote KEEP! They look great on you! The other pictures you've posted look nice, but I don't like any of them as well as the Pliners.
I have the Pliner boots and love them! I hadn't worn them until the last week or so because it's been hot here, but now that it's getting cooler I'm wanting to wear them all the time! I think the heel height is perfect- just low enough that they're totally comfortable to walk in, but not flat. I love the color, too- a beautifully complex shade of red that is not too bright, but still definitely red.
So far I've worn mine uncuffed with skinny jeans tucked into them, and I really like how they look. I'm sure I'll try them cuffed, too, just for variety.
I'll try to post an outfit picture soon. This past Sunday I wore them to breakfast at our local coffee shop with skinny jeans and an over-sized chambray shirt partially unbuttoned over a black tank. Totally simple, but I felt like the boots made the outfit so much more interesting. I wore them again today with black skinnies, a black tee, and a big slouchy black, gray and white patterned cardigan. Once again they made me feel fab as can be.
All that said, if you don't really love them then you should return them. But before you do, play around with some outfits. I really liked how they looked on you with that striped shirt.