Both are good names;I think I prefer Laura. I don't really get a similar vibe from the names, Julia I find a bit more patrician. Laura is a bit warmer.
I perfer Julia. Laura's lovely, but hard to write out after a bit. try it and see what I mean. L-around, up, up, up, and around. I've always had a problem writing out Laura. Maybe it's just me, though. But yes, I too get just about the same image from both names.