Good choice, I was in the same position as you a few days ago. I posted a question regarding it a few days ago.
(http://www.tomshardware.co.uk/answers/id-1869885/reference-reference-model.html)
I strongly recommend you wait for the after market coolers. They are much better than reference coolers (reference models run at 95°!), and YES, they overclock MUCH better (assuming you have a case with good airflow, etc).
And lastly, YES, they are DEFINITELY worth the extra cost (which isn't that much, maybe $10 or a $20 premium). You're investing a lot of money into your graphics card. $400 is a lot, so unless you want your graphics card to explode (which it probably won't) then you want a non-reference cooler. Also, if you're prone to NOISE and HEAT, then the reference model won't be ideal.
They will be arriving mid-late of this month, probably before the PS4's release date [which is Nov. 29th]
I think that covers about everything 😉