Watering With Rain Water

I am wondering if there is any advantage to watering my plants with rain water, i am on the west coast, so its easy to come by the ph of the tap and rain water are both the same right around 7.
I have been using tap water, just letting it set 24 hr. to evap the chlorine, I am in a major city so I would say it it safe to assume the tap water has a whole bunch of other s**t in it too, but then again so does rain water doesnt it?
what are the advantages and disadvantages?

Is it better... but probally not in the way your hoping. You wont get bigger buds (thats handled by the plants genes), but you are conserving water and being more "green." so ethically your a better person because your recycling instead of wasting communty water.

rain water is allways going to be better. tap water has all the shit in it.yes u can evaporate the chlorine/chloride but tap water also has all the metals and other crap

I use rain water when I can, if you're going to keep a large amount on hand I suggest putting a bubbler/air stone in it to keep it from going stagnant. Keep it covered too, skeeters love it.