I've got one of these on my team now. I wasn't planning on it, and I initially didn't like the design. Then a wonder trade dropped an Eevee mill reject on me, and since my planned team had only 5 members at that point I decided to make it a Sylveon. I don't know why it was rejected, whether the nature wasn't right for the planned evolution, it having a DW ability was wrong or if it just wasn't perfect in IVs, but I took it in.
Now its probably my favorite on my team so far, and kicking plenty of ass. I only wish I could name him Lancelot, since it seems like a good name for a dragonslayer on a team with mech names.
It was first to reach full poke aime affection with me as well.