I haven't stayed at either property, though I know the neighborhoods each is situated in. Colonia Condesa is more "hip" but Colonia Roma is probably more "mature". Both are excellent places to situate yourself. Condesa probably has more nightlife/restaurant options available. They'll be more well-known. Colonia Roma, though, is no shrinking Violet. My "gut" tells me Condesa DF is probably where you'll be most satisfied.