Notational Comfort

In regards to what is more comfortable to read, I have been struggling between 2 ways of notating the same 6/8 rhythm.  

 using ties

  not using ties

Which, out of the 2 bars above, is the preferred way to notate such rhythms for the sake of simplicity and quick understanding by the musician being asked to read?  

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Also, when writing out a part for a harpist, I read that it is customary to forego writing out the rests unless an intended rest is actually to be played (i.e. the harp is a naturally legato instrument).  Out of the two bars below, and with respect to how a harpist would like to see the notation, is either one better than the other?  The music outlined by the written bars here is, in fact, legato (no rests), however, I didn't want to break the reading musician's ability to count into a measure using any visible rests (especially for more complicated bars of music than pictured here).            

 rests

 no rests

well as a piano/guitar player either or should be easy enough to read for the 6/8 rhythm. Tied notes and dotted notes should be a concept that most people should grasp. For the ones unfamiliar with dotted notes I guess the one very specific should work out well so that it is well annotated. Due to its half value of the note it is being tied to. 

I prefer the non-tied notation. I'm not a harpist, so I can't speak to your second question.