I prefer Interlingua because it is comprehensible right from the start if you speak a Romance language and I imagine it is sufficiently comprehensible for an English speaker. There's this saying that it is "a language you already know but have never learned". This is done through more natural semantics and syntax.

About this following part, I'm not sure, but I've heard they also call it "the modern Latin". As I understand it, in order to be decipherable to all Romance languages speakers, it employs old Latin roots (with variations). The cool part, in case this is correct, is that we all know some of these words via science, arts, philosophy... (aqua, caelum, ovum...).