I have two of them: black and purple. I've been living in them for over a month now. I don't wear a cami underneath mine and they seem fine. It really all depends on your comfort level, but I find the solid ones to be not as sheer as the printed hearts.
Peri is right about the lack of breatheability. It's been chillier lately so it's fine. Watch out for deals too because the prices can go down quite a bit!